1. |
Fumiko Otsuka, Shuichi Matsukiyo, Tohru Hada, PIC simulation of a quasi-parallel collisionless shock: Interaction between upstream waves and field-aligned ion beams, ISEE symposium, 2019.02. |

2. |
Shuichi Matsukiyo, Keisuke Shimokawa, Haruichi Washimi, Tohru Hada, Gary P. Zank, Test particle simulation of cosmic ray invasion into the heliosphere, ISEE symposium, 2019.02. |

3. |
Yasuhiro Nariyuki, Makoto Sasaki, Tohru Hada, Stochastic modeling of pitch angle diffusion by parallel propagating magnetohydrodynamic waves, ISEE symposium, 2019.02. |

4. |
T. Hada, Y. Narita, Y. Nariyuki, Correlations between plasma density and magnetic field strength in MHD turbulence in space, JPGU, 2019.05, Large amplitude magnetohydrodynamic (MHD) turbulence is ubiquitous in space plasma, for example, in the solar wind, in the foreshock region (Narita, World Scientific, 2010) and in the sheath region of the earth's bowshock (e.g., Pollock et al., J. Atmosph. Solar Terr. Phys, 2018). Moreover, recent Voyager observations of large amplitude density and magnetic field fluctuations in the heliosheath behind the termination shock arouse a vivid discussion on the compressible nature and the origin of the observed turbulence (Burlaga and Ness, ApJ, 2009; Gutynska et al., ApJ, 2010). An obvious way of generating the density fluctuations is via the presence of compressive wave modes, such as obliquely propagating MHD waves. The density response is linear to the magnetic field perturbations in this case, and it vanishes in the limit of parallel wave propagation. In a finite (large) amplitude Alfvenic turbulence the density perturbation may be mainly generated via the "frozen-in" of the magnetic field to the plasma or the static balance between the plasma pressure and the magnetic field. Both of these processes result in the quadratic response of the density to the magnetic field perturbations, although their correlation is positive for the former and negative for the latter. This simple fluid picture, sometimes referred to as the "quasi-static" approximation, is known to be significantly modified when the ion response to the turbulence is kinetically treated (Mjolhus and Wyller, Phys. Scripta, 1986; Medvedev and Diamond, Phys. Plasmas, 1996). In this presentation, we address this unsolved issue of the correlations between the plasma density and the magnetic field amplitude in the presence of finite amplitude MHD turbulence by performing hybrid simulations (kinetic ions + fluid electrons), and by examining the in situ Cluster spacecraft data of the foreshock plasma (Narita and Hada, Earth, Planets and Space, 2018).. |

5. |
K. M. Girgis, T. Hada, S. Matsukiyo, Space Weather Effects on High Energetic Proton Flux Response in South Atlantic Anomaly, JPGU, 2019.05. |

6. |
T. Hada, Anomalous transport of cosmic rays, ISEE symposium, 2019.02. |

7. |
Kirolosse M. GIRGIS, T. Hada, S. Matsukiyo, Variations of South Atlantic Anomaly due to Space Weather Conditions, SGEPSS, 2018.11. |

8. |
Kirolosse Girgis, T. Hada, S. Matsukiyo, Solar Wind Effects on South Atlantic Anomaly, AAPPS-DPP2018, 2019.11. |

9. |
Y. Nariyuki, T. Hada, Damping processes of large amplitude Alfven waves in the solar wind, AAPPS-DPP2018, 2019.11. |

10. |
T. Hada, Anomalous transport of cosmic rays in MHD turbulence, AAPPS-DPP2018, 2019.11. |

11. |
T. Hada, Anomalous convection diffusion model of cosmic rays, JpGU, 2017.05. |

12. |
S. Matsukiyo, K. Nakanishi, F. Otsuka, A. Kis, I. Lemperger, T. Hada, Effect of field-aligned-beam in parallel diffusion of energetic particles in the Earth's foreshock, American Geophysical Union General Assembly, 2016.12. |

13. |
N. Katsuki, S. Matsukiyo, T. Hada, Numerical simulation of virtual Thomson scattering measurement of non-equilibrium laboratory plasmas, SGEPSS, 2016.11. |

14. |
K. Suzu, T. Hada, S. Matsukiyo, Numerical simulation of plasma detachment, SGEPSS, 2016.11. |

15. |
S. Isayama, T. Hada, S. Shinohara, Numerical simulation of helicon plasma discharge, SGEPSS, 2016.11, Helicon plasma is a high-density and low-temperature plasma generated by the electromagnetic (helicon) wave excited in the plasma. The helicon plasma is expected to be useful for various applications. On the other hand, there still remain a number of unsolved important physical issues on the helicon plasma. One of them is the abrupt transition of the plasma density (the helicon jump) from the low -density ( ̃1017 /m3) to the high - density ( ̃1019 /m3) regime as the input power is gradually increased. Some theoretical models (K. P. Shamrai, 1997, F. F. Chen, 2007) predict that the transition of discharge modes is closely related to the stability of the steady state, in which the power absorbed and lost by the electrons is balanced. However, the physical mechanism behind the mode transition needs to be further investigated, since in previous models, such seemingly important effects are neglected as the plasma transport, spatial inhomogeneity of the plasma density and the electron temperature. In the present research, we study the mode transition process of the helicon discharge by constructing a fluid discharge model which includes the wave excitation, electron heating, the power balance between the absorbed energy and the energy loss, and the effects of plasma transport.. |

16. |
M. Nishimura, T. Hada, S. Matsukiyo, Analysis of magnetohydrodynamic turbulence in space using data obtained by multi-spacecraft experiments, SGEPSS, 2016.11. |

17. |
T. Hada, Fractional convection diffusion model for the cosmic ray transport, SGEPSS, 2016.11. |

18. |
K. Matoba, T. Hada, S. Matsukiyo, Test particle simulation on generation of plasma acceleration region by external rotating magnetic field, SGEPSS, 2016.11. |

19. |
R. Haba, T. Hada, S. Matsukiyo, Generation of electron anisotropies in the earth's magnetotail, SGEPSS, 2016.11. |

20. |
F. Otsuka, K. Wang, S. Matsukiyo, T. Hada, Pitch-angle and energy diffusion of radiation belt electrons by lower-hybrid waves near the geomagnetic equator, International Conference on Plasma Physics, 2016.06. |

21. |
K. Wang, C. H. Lin, T. Hada, Y. Nishimura, V. Angelopoulos, Pitch-angle distribution for electrons at dipolarization sites: radial dependence, International Conference on Plasma Physics, 2016.06. |

22. |
T. Hada, K. Wang, Generation of anisotropic electron distributions in the earth's magnetosphere, International Conference on Plasma Physics, 2016.06. |

23. |
Y. Kuramitsu et al (6/17), Extremely high-Mach number collisionless shock in laser-produced plasmas, International Conference on Plasma Physics, 2018.06. |

24. |
Hironori A. Fujii, Chikatoshi Satoh, Koh Ichiro Oyama, Susumu Sasaki, Yoshiki Yamagiwa, Mengu Cho, Tohru Hada, Masayoshi Y. Tanaka, Masaaki Inutake, Jean Pierre Lebreton, Alain Hilgers, Juan Sanmartin, Marrio Charro, Michiel Kruijff, Erick J. Van Der Heide, Giuliano Vannaroni, Les Johnson, Paul Wilbur, George V. Khazanov, Proposed space experiments of space tether technology, International Astronautical Federation - 56th International Astronautical Congress 2005, 2005, This paper is to introduce two space tether experimental projects including; 1) a sounding rocket experiment in a ballistic flight extending 1km bare tape tether, and 2) a small satellite experiment on a circular orbit with the altitude 600km extending 20km electro-dynamic tether. The sounding rocket experiment employs bare electro-dynamic tether for the following two missions, one is much fundamental to make measurement on the bare tether, and the other is to use the bare tether as an atmospheric probe. The small satellite proposal is to verify the fundamental technology for such important tether technology as deployment and use of bare conductive tether in space. The objective is to verify the two fundamental and important aspects of the tether technology including the orbit elevation without using fuel, and the Alfven wave experiment. These two projects towards space tether experiments are introduced in the paper and discussed in detail including the present status for the accomplishment of these projects. The paper will also include discussion of the further future plan to accomplish the space tether technology which will play an important role for our future space activity.. |

25. |
Kyoichiro Toki, Takashi Hashimoto, Kenji Makita, Shunjiro Shinohara, Tohru Hada, Yasushi Ikeda, Takao Tanikawa, Konstantin P. Shamrai, Ikkho Funaki, Small helicon source for electrocleless plasma production and electromagnetic acceleration, AIAA/ASME/SAE/ASEE 42nd Joint Propulsion Conference, 2006, A compact helicon source having an inner diameter of 2.5 cm with 46 cm long glass tube was investigated using a Boswell type antenna. Argon gas was fed into the glass tube from the upstream end at inner pressures, 10-40 mTorr corresponding to the mass flow rates, 0.5-2 mg/s. Two apparent jumps were observed with increasing RF power. The first jump took place at about 200 W RF input, from capacitively coupled plasma (CCP) to inductively coupled plasma (ICP), and the second jump was encountered at about 500 W RF input power from ICP to presumably the helicon mode. The maximum applied magnetic field was 800 gauss. The achieved plasma density exceeded 10^{13} cm^{-3} at the expected helicon mode. Based upon this result, a few concepts of electrodeless plasma acceleration techniques were suggested and also simulated by analyses. A preliminary experiment of the acceleration for proof-of-concept was conducted.. |

26. |
Fumiko Otsuka, Tohru Hada, Anomalous diffusion of cosmic rays in magnetic field turbulence - Linkage between diffusion statistics and turbulence statistics -, International Workshop on Complexity and Nonextensivity: New Trends in Statistical Mechanics, CN-Kyoto 2005, 2006.02, Anomalous diffusion of energetic charged particles (cosmic rays) is studied using a simple two-dimensional cross field diffusion model. Both super-diffusion and sub-diffusion can take place in the model. When typical Larmor radius of the particles is much less than the field correlation length, the particles essentially gradient-B drift along equi-contour lines of the magnetic field strength, and thus the diffusion in this parameter regime can essentially be understood by analyzing statistics of the magnetic field islands composed of these equi-contour lines. We numerically evaluate the statistics of the field islands such as the probability distribution function of island radius and fractal dimension of the island contour lines, as functions of the power-law index of the magnetic field turbulence. We find numerically and analytically the scaling laws of time-scale dependent diffusion coefficients using the parameters obtained by analysis of the field islands statistics.. |

27. |
Kyoichiro Toki, Takashi Hashimoto, Yoshikazu Tanaka, Shunjiro Shinohara, Tohru Hada, Yasushi Ikeda, Takao Tanikawa, Konstantin P. Shamrai, Ikkoh Funaki, Compact helicon source experiments for electrodeless electromagnetic thruster, 43rd AIAA/ASME/SAE/ASEE Joint Propulsion Conference, 2007, Ar plasma of 10^{13} cm^{-3} density was formed in a 2.5 cm i.d. helicon source and the acceleration experiments using RF antennae were performed. A repetitious saw-tooth coil current acceleration method and a continuous "Lissajous" acceleration method were tested. The latter method attained 3.5 km/s plasma exhaust velocity. Judging from the plasma properties measurements, this is thought to be an electromagnetic acceleration.. |

28. |
Kyoichiro Toki, Shunjiro Shinohara, Takao Tanikawa, Tohru Hada, Ikkho Funaki, Yoshikazu Tanaka, Akihiro Yamaguchi, Kostiantyn P. Shamrai, On the electrodeless MPD thruster using a compact helicon plasma source, 44th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 2008, Helicon wave excitation is one of the promising RF plasma production methods. It produces high density plasma (∼10^{13} cm^{-3}) that enables electromagnetic acceleration. We prepared the acceleration coil or 2 pairs of copper plates around the glass tube. These acceleration methods are called a repetitious coil current acceleration and a continuous "Lissajous" acceleration, respectively. When the repetitious coil acceleration was applied, the maximum plasma velocity of 3.6 km/s was 76% velocity increment compared with before acceleration with the absorbed plasma production + acceleration power of (400+180) W and the applied magnetic field strength of 1,450 gauss. As for the "Lissajous" acceleration, the plasma velocity was 2.2 km/s with the absorbed plasma production + acceleration power of (290+200) W. However it is suggested that these accelerations remain in the thermal acceleration regime judging from the electron temperature or density increase.. |

29. |
Taisei Motomura, Shunjiro Shinohara, Takao Tanikawa, Tohru Hada, Ikkoh Funaki, Hiroyuki Nishida, Konstantin P. Shamrai, Takeshi Matsuoka, Fumiko Otsuka, Timofei S. Rudenko, Eiji Ohno, Kenji Yokoi, Takahiro Nakamura, Development of electrodeless electric propulsion systems using high-density helicon plasmas The HEAT project, 2011 30th URSI General Assembly and Scientific Symposium, URSIGASS 2011, 2011, In order to develop completely electrodeless next generation plasma thrusters for deep space missions, we have initiated the HEAT (Helicon Electrodeless Advanced Thruster) project. In our scheme, source plasmas are generated by means of the highly efficient helicon-wave discharge; they are then electromagnetically accelerated using external antennas to yield a thrust. The entire process can be achieved without using any eroding electrodes, leading to plasma thrusters of a limitless lifetime.. |

30. |
Takeshi Matsuoka, Ikkoh Funaki, Syuhei Satoh, Takayasu Fujino, Shota Iwabuchi, Takahiro Nakamura, Hiroyuki Nishida, Shunjiro Shinohara, Takao Tanikawa, Tohru Hada, Konstantin P. Shamrai, Laboratory model development of Lissajous acceleration for electrodeless helicon plasma thruster, 48th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit 2012, 2012, A thrust model for a Lissajous method has shown that a competitive performance compared with the rockets using, e.g., ion engines or Hall thrusters, can be achieved by electrodeless method which can be a long lived thruster. Previous experiments showed a slight increase of plasma flow velocity by this method, however, experimental conditions were not optimized and the thrust was not measured. In this study, two experiments are reported in order to develop helicon plasma sources and a thrust measurement method by using Ar gas propellant. The first experiment is measurements of thermal thrust in order to characterize thruster performance 26 mm and 50 mm diameter helicon plasma thrusters without Lissajous acceleration. Maximum specific impulse (390 ± 130 s) is observed at a parameter set: the mass flow rate of 0.24 mg/s, the magnetic field: B_{Z} = 0.054 T and RF (radio frequency) input power of 2.0 kW when a 50 mm diameter thruster is used. It is found that the thrust and efficiency is proportional to absorbed power by the plasma. The second experiment is preliminary measurements of Lissajous acceleration by using a laboratory model of 50 mm diameter. Preliminary thrust measurements by using the laboratory model show clear plasma acceleration by applying acceleration power. The observed thrust with acceleration power of 130 W is 3.3±0.3 mN with a specific impulse of 380±40 s and efficiency. |

31. |
Kenji Takahashi, Takahiro Nakamura, Hiroyuki Nishida, Shunjiro Shinohara, Takaeshi Matsuoka, Ikkoh Funaki, Takao Tanikawa, Tohru Hada, Study for direct measurement of electromagnetic thrust of electrodeless helicon plasma thruster, 13th International Space Conference of Pacific-Basin Societies, ISCOPS 2012, 2013, Conventional electric propulsion systems have some problems about the lifetime due to the erosion of electrodes caused by contacts between electrodes and the plasma. In order to solve this problem and realize the infinite life-time electric thrusters, we aim for a development of a completely electrodeless electric thruster. We have constructed a laboratory model of the electrodeless plasma thruster adopting the Lissajous plasma acceleration and a thrust stand to measure the electromagnetic thrust for validating our plasma acceleration concept. In this paper, we report the designing of the magnetic circuit using permanent magnets and the thrust stand. And the result of the thrust stand calibration and the progress of the thrust measurements are reported.. |

32. |
Takahiro Nakamura, Hiroyuki Nishida, Takeshi Matsuoka, Ikkoh Funaki, Shunjiro Shinohara, Takao Tanikawa, Tohru Hada, Konstantin P. Shamrai, Timofei S. Rudenko, Probe measurement of plasma plume on electrodeless helicon plasma thruster using Lissajous acceleration, 13th International Space Conference of Pacific-Basin Societies, ISCOPS 2012, 2013, In order to realize a long-lived electric propulsion system, we have been investigating an electrodeless plasma thruster concept utilizing a helicon plasma source and Lissajous plasma acceleration, which uses the static diverging magnetic field and a rotating electric field (REF). Using a laboratory model of the Lissajous acceleration-type thruster, plasma acceleration experiments have been conducted. In the experiments, plasma flow velocity was measured at the center in the thruster using a para-perp type Mach probe. It was observed that the application of the REF power (13.56 MHz, 1.4kV_{p-p}) makes in increase in the plasma flow velocity. In addition, axial distributions of the plasma velocity indicate that the particle collision between neutral gas and plasma particle has a significant effect on the plasma expansion process in the magnetic nozzle.. |

33. |
S. Shinohara, H. Nishida, T. Tanikawa, Tohru Hada, I. Funaki, K. P. Shamrai, Characterization of developed high-density helicon plasma sources and Helicon Electrodeless Advanced Thruster (HEAT) project, 2013 19th IEEE Pulsed Power Conference, PPC 2013, 2013, Helicon sources are very effective in many aspects and are applicable in various science and technology fields, since they can supply high-density (∼ 10^{13} cm^{-3}) plasmas with flexible operating parameters. In this paper, we characterize developed, featured sources in various sizes along with a discussion on a particle production efficiency. This activity was performed within the HEAT (Helicon Electrodeless Advanced Thruster) project aiming at development of the systems that can realize the schemes of completely electrodeless plasma production and acceleration. This is expected to mitigate a problem of finite life time inherent to electrodic plasma propulsion tools. Experimental and theoretical approaches to implementation of such the schemes are presented.. |

34. |
Kaiti Wang, C. H. Lin, T. Hada, Y. Nishimura, V. Angelopoulos, W. J. Lee, Pitch-Angle Distribution for Electrons at Dipolarization Sites: field aligned anisotropy and isotropization, American Geophysical Union Annual Meeting, 2015.12. |

35. |
T. Hada, F. Otsuka, S. Isayama, S. Shinohara, H. Nishida, T. Tanikawa, I. Funaki, Modeling of helicon plasma production and plasma acceleration, Plasma 2014, 2014.11. |

36. |
S. Isayama, T. Hada, S. Shinohara, T. Tanikawa, Modeling of Helicon Wave Propagation and the Physical Process of Helicon Plasma Production, APS/DPP (American Physical Society, Division of Plasma Physics) Annual Meeting, 2014.10, Helicon plasma is a high-density and low-temperature plasma generated by the helicon wave, and is expected to be useful for various applications. On the other hand, there still remain a number of unsolved physical issues regarding how the plasma is generated using the helicon wave. The generation involves such physical processes as wave propagation, mode conversion, and collisionless as well as collisional wave damping that leads to ionization/recombination of neutral particles. In this study, we attempt to construct a model for the helicon plasma production using numerical simulations. In particular, we will make a quantitative argument on the roles of the mode conversion from the helicon to the electrostatic Trivelpiece-Gould (TG) wave, as first proposed by Shamrai. According to his scenario, the long wavelength helicon wave linearly mode converts to the TG wave, which then dissipates rapidly due to its large wave number. On the other hand, the efficiency of the mode conversion depends strongly on the magnitudes of dissipation parameters. Particularly when the dissipation is dominant, the TG wave is no longer excited and the input helicon wave directly dissipates. In the presentation, we will discuss the mode conversion and the plasma heating using numerical simulations.. |

37. |
S. Shinohara, D. Kuwahara, T. Nakagawa, S. Isayama, T. Hada, Thrust Characteristics of Helicon Plasma Thrusters, APCPST 2014 (Asia Pacific Conference on Plasma Science and Technology), 2014.09. |

38. |
S. Shinohara, D. Kuwahara, T. Nakagawa, K. Yano, S. Isayama, T. Hada, High-density helicon plasma sources and their characteristics, APCPST 2014 (Asia Pacific Conference on Plasma Science and Technology), 2014.09. |

39. |
T. Hada, Statistics of Energetic Particles in a Non-uniform Plasma Flow, AOGS2014 (Asia Oceania Geophysical Society Annual Meeting 2014), 2014.07, It is well known that energetic particles such as cosmic rays in space can efficiently be accelerated by scatterers convected by a compressional flow (Fermi acceleration). Scatterers convected by an expanding flow decelerate the particles, but this is not the reverse process of the acceleration. Plasma in space is never uniform, but is rather composed of different plasmas with different propagation speeds. We analyze statistics of energetic particles in such nonuniform plasma flow analytically and numerically. Results will be compared with non-equilibrium plasma distributions in the solar wind. . |

40. |
S. Isayama, T. Hada, S. Shinohara, T. Tanikawa, Thrust Performance of High Magnetic Field Permanent Magnet Type Helicon Plasma Thruster, AIAA Propulsion and Energy Forum and Exposition 2014, 2014.07. |

41. |
M. Nakanotani, S. Matsukiyo, T. Hada, Numerical experiment of two colliding shocks, AOGS2014 (Asia Oceania Geophysical Society Annual Meeting 2014), 2014.07, A well-accepted mechanism that can explain a number of observed features of cosmic rays (high-energy charged particles) is Fermi acceleration by collision-less shock waves. Although there are many studies on this subject, most of them assume there is only a single shock that accelerates the cosmic rays. However, there are a countless number of shock waves in space, and they frequently approach and collide. In the heliosphere, for example, the interplanetary shocks often collide with the Earth’s bow shock [H. Hietala et al., 2011] or with the heliospheric termination shock [J. Y. Lu et al., 1999]. We consider the structure and particle acceleration by colliding shocks. A previous work using hybrid simulation [Cargill et al., 1986] reports efficient ion acceleration when supercritical shocks collide. In the hybrid simulation, however, the electron dynamics cannot be resolved. We perform full Particle-in-Cell (PIC) simulation to study evolution of micro-structures as well as the ion and electron acceleration processes as two super-critical shocks with various shock parameters (Mach number MA, plasma beta β, shock angle θBn) collide against each other. We will report details of the electron acceleration. . |

42. |
Y. Nariyuki, T. Hada, K. Tsubouchi, Ion Kinetics and Nonlinear Evolution of Alfvenic Turbulence in the Radially Expanding Solar Wind, AOGS2014 (Asia Oceania Geophysical Society Annual Meeting 2014), 2014.07, Ions in non-equilibrium such as ion beams and Alfvenic turbulence are often observed in solar wind plasmas. In the present study, ion kinetics and nonlinear evolution of low-frequency Alfvenic turbulence is discussed by using a hybrid expanding box model (HEBM). The growth of ion beam instabilities is affected by both the inhomogeneity of the background plasmas and low-frequency Alfvenic turbulence. It is interesting that the nonlinear evolution of Alfvenic turbulence is also affected by the growth of ion beam instabilities. The resultant growth of instabilities and energy dissipation of Alfvenic turbulence are numerically discussed.. |

43. |
Takahiro Nakamura, Sho Ito, Hiroyuki Nishida, Shunjiro Shinohara, Ikkoh Funaki, Takao Tanikawa, Tohru Hada, Thrust performance of high magnetic field permanent magnet type Helicon Plasma Thruster, 50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and exhibit 2014, 2014.01, In order to realize long-lived electric propulsion systems, we have been investigating an electrodeless plasma thruster. In our concept, high-density helicon plasma is accelerated by a magnetic nozzle for thrust production. In order to improve the thrust performance with simple systems, high magnetic flux density magnetic nozzle formed by permanent magnets is employed to our laboratory model plasma thruster. A magnetic circuit, which has high magnetic flux density up to 0.2 T at the magnetic nozzle throat, is constructed by permanent magnets and magnetic yoke. In order to investigate the thrust performance of this thruster, the thrust force is measured by a torsion-pendulum type thrust stand. From the thrust measurement, the thrust force and specific impulse increases with the RF power input. The thrust efficiency is drastically improved by increasing the RF power input, and it is considered to be caused by the discharge mode transition from the CCP to the ICP. The maximum thrust force and thrust efficiency of 2.7 ± 0.4 mN and 0.26 % is measured when the Ar gas mas flow rate is 1.2 mg/s, and plasma production frequency and power is 13.56 MHz and 1000 W.. |

44. |
M. G. Cardinal, A. Yoshikawa, H. Kawano, H. Liu, M. Watanabe, S. Abe, T. Uozumi, G. Maeda, T. Hada, K. Yumoto, Capacity building activities at ICSWSE, International CAWSES-II Symposium, 2013.11. |

45. |
Y. Kuramitsu et al, T. Hada (10/32), Laboratory simulations of space and astrophysical phenomena, AP-RASC13 (Asia Pacific Radio Science Conference 2013), 2013.09. |

46. |
F. Otsuka, T. Hada, S. Shinohara, T. Tanikawa, Numerical studies of ponderomotive acceleration/ion cyclotron resonance for electrode less electric thruster, AP-RASC13 (Asia Pacific Radio Science Conference 2013), 2013.09. |

47. |
T. Hada, F. Otsuka, S. Shinohara, H. Nishida, T. Tanikawa, I. Funaki, Development of electrode less helicon plasma thrusters, AP-RASC13 (Asia Pacific Radio Science Conference 2013), 2013.09. |

48. |
S. Shinohara, T. Tanikawa, T. Hada, I. Funaki, H. Nishida, F. Otsuka, D. Kuwahara, K. P. Shamrai, Characterization of high-density helicon plasma sources and application to electrode less plasma thrusters, AP-RASC13 (Asia Pacific Radio Science Conference 2013), 2013.09. |

49. |
T. Hada, Diffusive shock acceleration of cosmic rays with non-Gaussian transport, The 11th International School for Space Simulations, 2013.07, It is widely recognized that the diffusive shock acceleration (DSA) is the most likely acceleration process responsible for producing the observed power law cosmic ray spectrum, at least up to the so-called knee energies. One of the key elements of the DSA is the scattering of the cosmic rays by MHD turbulence, which is believed to exist both shock upstream and downstream. As the cosmic rays are repeatedly scattered by the MHD turbulence, they travel back and forth across the shock and energized by effectively compressed by the convergent background plasma flow. While majority of past studies on the DSA employ quasi-linear type model for the cosmic ray diffusion, actual transport of the cosmic rays in plasma with MHD turbulence can be qualitatively different. In the quasi-perpendicular shock geometry, the cosmic ray diffusion may be sub-diffusive when the particles are trapped by the guiding field. In contrast, parallel diffusion of the cosmic rays may be considered super-diffusive when a time scale considered is less than the mixing (reflection) time scale. In the presentation, we first explain basics of the DSA process and the non-Gaussian transport of particles, and then discuss results of our test particle simulations of the DSA in which the scattering of particles is specified by several different diffusion models. Cosmic ray spectrum index as well as spatial profile of the cosmic ray intensity are evaluated and discussed for both sub-diffusive and super-diffusive cases. . |

50. |
F. Otsuka, T. Hada, S. Shinohara, T. Tanikawa, I. Funaki, Ponderomotive acceleration for electrode less electric thruster: effect of electromagnetic field penetration into magnetized plasmas, APPC12 (The 12th Asia Pacific Physics Conference of AAPPS), 2013.07. |

51. |
K. Nakanotani, S. Matsukiyo, T. Hada, Full particle-in-cell simulation of two colliding shocks, APPC12 (The 12th Asia Pacific Physics Conference of AAPPS), 2013.07. |

52. |
T. Hada, Y. Nariyuki, Y. Narita, Evaluation of higher order statistics of MHD turbulence using multi-spacecraft data, APPC12 (The 12th Asia Pacific Physics Conference of AAPPS), 2013.07, Magnetohydrodynamic (MHD) waves are ubiquitous in space plasma. In particular, those found in the foreshock region of the earth’s bowshock often have order of unity normalized wave amplitude of the magnetic field, and due to this large amplitude one has a possibility to directly observe nonlinear interaction among the waves. It is thus important to develop a robust and accurate method that can extract as much information as possible on the nonlinear behavior of the MHD waves, using the field and plasma data obtained from multi-point measurement. In this presentation we demonstrate that the higher-order statistics [1] of the MHD turbulence can be evaluated both in time and spatial (i.e., both in the frequency and the wave number) domains. Compared with the analysis in the time domain, that in the spatial domain is severely restricted due to a small number of data points, since the number of spacecraft in typical formation flights is less than five. However, the so-called Capon’s method has been successfully adopted in determination of the wave number spectra for Cluster experiments[2,3]. We show that the Capon’s method is also useful in evaluation of the bispectrum and the bicoherence[4]. Accuracy and robustness to the noise of the proposed method will be tested using data obtained by numerical simulations and also by the Cluster experiments. [1] T. Dudok de Wit, in Space Plasma Simulation, eds., J. Bu ̈chner et al., Springer, Berlin (2003) [2] U. Motschmann et al., J. Geophys. Res., 101, 4961-4965, (1996) [3] J. L. Pin ̧con and F. Lefeuvre, J. Geophys. Res., 96, 1789-1802, (1991) [4] Y. Narita et al., Ann. Geophys., 26, 3389-3393, (2008). |

53. |
T. Hada, F. Otsuka, S. Shinohara, H. Nishida, T. Tanikawa, I. Funaki, Research and development of electrodeless helicon plasma thrusters, IPELS013 (The 12th Int'l Workshop on the Interrelationship between Plasma Experiments in Laboratory and Space), 2013.07, Electric thruster is a form of spacecraft propulsion that uses electric energy to accelerate plasma propellant. Due to its large specific impulse, the electric thrusters are suited for long duration operations such as missions to outer planets. On the other hand, the performance of many of the conventional electric thrusters is severely limited by electrode wastage. In order to overcome this difficulty, we have been conducting the HEAT (Helicon Electrodeless Advanced Thruster) project to pursue research and development of electrodeless plasma thrusters. In the presentation, we first briefly describe the background and the targets of the project, and then introduce the concepts of electrodeless plasma production using the so-called helicon waves (i.e., bounded whistler waves) and the electrodeless plasma acceleration via externally applied time-varying electromagnetic fields. In particular, we discuss some details on the three plasma acceleration schemes we consider: the Rotational Magnetic Field (RMF), the Rotational Electric Field (REF), and the Ponderomotive Acceleration (PA) schemes. Although the helicon plasma is collisional and dissipative, it shares many intrinsic features with space plasmas, implying that there are possibilities that people in space plasma community make substantial contributions in the field of electric thrusters. Theory and simulation results as well as recent laboratory experiments will be discussed. . |

54. |
Injection problem in collisionless shocks. |

55. |
羽田 亨, 大塚史子, 篠原俊二郎, 西田浩之, 谷川隆夫, 船木一幸, Electrodeless Plasma Thrusters: Nonlinear wave acceleration of a helicon plasma, International Nonlinear Waves and Chaos Workshop, 2013.03, Electric thruster is a form of spacecraft propulsion that uses electric energy to accelerate plasma propellant. Due to its large specific impulse, the electric thrusters are suited for long duration operations such as missions to outer planets. On the other hand, the performance of many of the conventional electric thrusters is severely limited by electrode wastage. In order to overcome this difficulty, we have initiated the HEAT (Helicon Electrodeless Advanced Thruster) project to pursue research and development of completely electrodeless plasma thrusters. In the presentation, we first briefly describe the background and the targets of the project, and then introduce the concepts of electrodeless plasma production using the so-called helicon waves (i.e., bounded whistler waves) and the electrodeless plasma acceleration via externally applied time-varying electromagnetic fields. In particular, we discuss some details on the three plasma acceleration schemes we consider: the Rotational Magnetic Field (RMF), the Rotational Electric FIeld (REF), and the Ponderomotive Acceleration (PA) schemes. Although the helicon plasma is collisional and dissipative, it shares many intrinsic features with space plasmas, implying that there are possibilities that people in space plasma community make substantial contributions in the field of electric thrusters. Theory and simulation results as well as recent laboratory experiments will be discussed. . |

56. |
Test particle simulation of diffusive shock acceleration process in a cosmic ray mediated shoc . |

57. |
Multi-spacecraft observation of the non-stationary terrestrial bow shock. |

58. |
Research and development of next generation electrodeless plasma thrusters using helicon source. |

59. |
Tohru Hada, Some modern analyses of space plasma waves, International Space Weather Initiative, 2012.09. |

60. |
Tohru Hada, Yasuhiro Nariyuki, Yasuto Narita, Higher order statistics of MHD turbulence using multi-spacecraft data, Asia Oceania Geophysics Society Annual Meeting, 2012.08. |

61. |
Nonlinear excitation of high phase velocity non-MHD waves associated with solar flares
Ion distributions with temperature anisotropy is often formed at the solar surface during flares. These ions with perpendicular temperature greater than parallel temperature easily excite parallel propagating ion cyclotron waves. Since the plasma at the solar surface contains substantial portion of heavy ions, we need to make use of a dispersion relation in a multi-component plasma, which is quite different from that in a single component plasma. In particular, introduction of the heavy ions splits the ion mode into two branches, and a 'non-MHD part' of the upper branch at small wave numbers can efficiently accelerate particles since the waves in this regime can have large electric field. On the other hand, these waves have not been given proper attention as they are hardly excited by linear process (as they are very much off resonance), and are only poorly described by MHD or hybrid simulation models due to the large phase speed. In this presentation, we discuss long time evolution of ion cyclotron instability in the multi-component plasma by performing full particle simulations. We will show that the high phase velocity non-MHD waves are naturally excited as a nonlinear consequence of the ion cyclotron instability. Details of the simulation results including wave spectrum and particle acceleration will be presented. . |

62. |
Ponderomotive acceleration in a realistic magnetic field and plasma configuration
Electric thrusters, characterized with high specific impulse, are considered to be useful for long-term space missions such as those to outer planets. On the other hand, the performance of many of the conventional electric thrusters (e.g., ion engines) is limited by electrode wastage. In order to overcome this difficulty, we have initiated the HEAT (Helicon Electrode less Advanced Thruster) project, in order to pursue research and development of completely electrode less thrusters. Among several plasma acceleration schemes we propose, we here discuss the so-called ponderomotive acceleration, in which ions are accelerated by ponderomotive force produced by externally given electromagnetic RF waves. We first discuss briefly test particle simulation results for simplified magnetic field and plasma configuration. As pointed out by previous authors, ions are axially accelerated by the ponderomotive force, while the axial acceleration is also caused by resonant ion cyclotron heating by the external RF waves and subsequent mirroring of ions in the divergent magnetic field. Then we discuss the acceleration using magnetic field and plasma configuration which models the Tokai University Helicon Device. Of particular importance is the plasma shielding effect. Using realistic parameters, we give an estimate of the ponderomotive acceleration that can be compared with experimental studies. . |

63. |
Relativistic particle acceleration in developing Alfven turbulence. |

64. |
Interactions among foreshock MHD waves and consequences. |

65. |
Correlation between density and magnetic field fluctuations associated with dissipation of quasi-parallel Alfven waves. |

66. |
Self-generation of phase coherence in multiply-coupled triplet system. |

67. |
Nonlinear interaction and interactive states in a simple weak turbulence model by multiply-coupled triplets. |

68. |
A new exact solution of finite amplitude Alfven wave in a relativistic pair plasma. |

69. |
Dispersion relation of finite amplitude Alfven wave in a relativistic electron-positron plasma. |

70. |
Analysis of weak turbulence model composed of multiply-coupled triplets: nonlinear interactions and relative states. |

71. |
Time evolution of phase coherence among MHD waves: DNLS simulation study. |

72. |
Field-aligned diffusion of energetic particles in turbulent magnetic field: dependence on the turbulence statistics. |

73. |
Nonlinear dispersion relation of finite amplitude relativistic Alfven waves. |

74. |
A new exact solution of finite amplitude Alfven wave in a relativistic pair plasma. |

75. |
New statistical analysis of nonlinear MHD waves in the solar wind. |

76. |
A simple model of weak turbulence by multiply-coupled triplets: intermittency and power-law. |

77. |
A new exact dispersion relation of finite amplitude Alfven wave in a relativistic pair plasma. |

78. |
Geotail observation and numerical simulation of shocklets in the earth's foreshock. |

79. |
Time series analysis of Non-Brownian motion and its application to diffusion of energetic particles in turbulent magnetic field. |

80. |
On relationship between phase coherence among Fourier modes and temporal phase synchronization. |

81. |
Phase coherence among MHD waves in the solar wind: statistical analysis. |

82. |
Nonlinear Alfven waves in the Earth's foreshock: theory, observation, and numerical simulations. |

83. |
The maximum energy attained by the shock diffusive acceleration. |

84. |
On Correlation Between the Magnetic and the Density Fluctuations in Large Amplitude MHD Turbulence. |

85. |
Phase correlation among MHD waves in the earth's foreshock region. |

86. |
Field-aligned diffusion of charged particles in MHD turbulence: comparison with quasi-linear theory. |

87. |
Statistical analysis of shocklets in the earth's foreshock using Geotail magnetic field data. |

88. |
On correlation between magnetic and density fluctuations in large amplitude MHD turbulence. |

89. |
Statistical analysis of shocklets in the earth's foreshock using Geotail magnetic field data. |

90. |
Phase synchronization of MHD waves in the earth's foreshock region. |

91. |
Multiply coupled triplets as a simple model of weak turbulence: intermittency and power-law. |

92. |
Pitch angle diffusion of energetic particles by large amplitude MHD waves. |

93. |
Non-classical diffusion of energetic particles in two dimensional magnetic field turbulence. |

94. |
Evaluation of phase coherence among MHD waves. |

95. |
Origin of phase coherence among MHD waves in the solar wind. |

96. |
Development of Space Simulation Net Laboratory System. |

97. |
Statistical analysis of shocklets in the earth's foreshock using Geotail magnetic field data. |

98. |
Time series analysis of non-Brownian motion. |

99. |
Phase correlation among MHD waves - fundamental characteristics. |

100. |
On correlation between magnetic and density fluctuations in space plasma. |

101. |
Multiply coupled triplets as a simple model of weak turbulence: intermittency and power-law. |

102. |
Phase coherence of large amplitude MHD waves in the earth's foreshock. |

103. |
Some new statistical studies on MHD turbulence in the solar wind. |

104. |
Anomalous diffusion of energetic particles in MHD turbulence. |

105. |
Field aligned diffusion of charged particles due to magnetic pulses. |

106. |
A simple model of super-diffusion of energetic particles in MHD turbulence. |

107. |
Nonlinear statistical analysis of solar wind magnetic field data. |

108. |
Particle diffusion in the turbulent MHD field. |

109. |
Structual and micro-instabilities of collisionless shock waves. |

110. |
Phase coherence of large amplitude MHD waves in the earth's foreshock. |

111. |
Transport of Energetic Particles in a Space Plasma. |

112. |
Nonlinear evolution of Alfven turbulence in the solar wind. |

113. |
Phase coherence of large amplitude MHD waves in the earth's foreshock: Geotail observations. |

114. |
Patterns and chaos in the DNLS equation subject to driving and dissipation. |

115. |
Phase coherence of large amplitude MHD waves in the earth's foreshock: Geotail observations. |

116. |
Cross-field diffusion of cosmic rays: Levy statistical analysis. |

117. |
Field aligned diffusion of cosmic rays by MHD turbulence. |

118. |
Time evolution of phase coherence due to wave-wave interactions. |

119. |
Numerical simulation study of plasma masers. |

120. |
Phase correlation analysis of hydromagnetic turbulence in the solar wind. |

121. |
Parametric decay instabilities of Alfven waves in a strongly relativistic electron-positron plasma. |

122. |
Nonlinear statistical analysis of solar-terrestrial magnetic field time series data. |

123. |
Shock front nonstationarity of supercritical perpendicular shock: an extended parametric study. |

124. |
Diffusion of energetic particles by MHD waves in space. |

125. |
On phase correlation of plasma waves in space. |

126. |
Consequences of Soliton Acceleration: Statistical Model. |

127. |
Self-organized criticality of the Magnetotail. |

128. |
Phase correlation of lage amplitude MHD waves in the earth's foreshock. |

129. |
Phase coherence among large amplitude hydromagnetic waves observed by Geotail spacecraft: statistical analysis. |

130. |
Self-organized criticality model of the magnetotail: the effect of background current. |

131. |
Parametric instabilities in a relativistic electron-positron plasma. |

132. |
Pitch angle diffusion of charged particles by MHD turbulence. |

133. |
A new nonlinear statistical analysis of solar wind magnetic field time series. |

134. |
Super-diffusion of charged particles in a space plasma. |

135. |
Cross-field diffusion of cosmic rays in the incompressible magnetic field turbulence. |

136. |
On routines to analyze spacecraft data. |

137. |
Development of space simulation / net-laboratory system. |

138. |
Cross field transport of cosmic rays: Test particle simulation studies. |

139. |
Energy diffusion of charged particles by MHD waves: deviation from quasi-linear theory. |

140. |
Nonstationarity of super-critical perpendicular shocks. |

141. |
Pitch angle diffusion of charged particles by MHD turbulence. |

142. |
Transport of Energetic Particles in a Space Plasma. |

143. |
Nonstationarity of collisionless shock waves. |

144. |
Phase correlation in the MHD turbulence in the solar wind. |

145. |
Correlation analysis of large amplitude MHD waves using Geotail spacecraft data. |

146. |
Quasi-stability of the k=0 mode excited by the relativistic ring distribution. |

147. |
Some novel analyses of MHD turbulence in the solar wind. |

148. |
Self-organized criticality of magnetotail. |

149. |
Behavior of low energy particles and magnetic field variations at geo-synchronous orbit associated with auroral phenomena. |

150. |
Pitch angle scattering of charged particles by obliquely propagating MHD waves. |

151. |
Nonlinear interaction between charged particles and an MHD pulse. |

152. |
Nonstationary super-critical perpendicular shock waves. |

153. |
Cross field diffusion of cosmic rays in a turbulent magnetic field: percolation statistics. |

154. |
Large scale nonstationarity of a quasi-perpendicular supercritical shock wave: multi-fluid and PIC simulations comparison. |

155. |
Cross-field diffusion of high energy particles in a two-dimensional magnetic field. |

156. |
Spatio-temporal behavior in a driven system of MHD waves. |

157. |
Acceleration of relativistic particles by large amplitude MHD waves:a statistical model. |

158. |
Pitch angle diffusion of charged particles by finite amplitude MHD waves. |

159. |
STE research from the complex dynamial systems point of view. |

160. |
An auroral breakup event as observed by all-sky image and magnetometer at synchronous altitude. |

161. |
Nonlinear evolution of Alfven waves. |

162. |
Nonlinear evolution of relativistic ring instability. |

163. |
Soliton acceleration: relativistic effects. |

164. |
Cross-field transport of cosmic rays. |

165. |
On nonstationarity of super-critical perpendicular shocks. |

166. |
Multiscale reconnection in the magnetotail. |

167. |
Mulit-scale reconnection in the earth's magnetotail. |

168. |
Levy process and its applications: acceleration of charged particles in a space plasma. |

169. |
Transport of cosmic rays in a turbulent magnetic field. |

170. |
Acceleration and diffusion of energetic particles by MHD waves: beyond quasi-linear theories. |

171. |
Pitch angle diffusion of charged particles by large amplitude MHD waves. |

172. |
Transport of cosmic rays in a turbulent magnetic field: test particle simulations. |

173. |
Relativistic soliton acceleration. |

174. |
Jeans instability in a plasma including neutral particles. |

175. |
Phase transition approach to the nonlinear waves driven by a relativistic ring distribution. |

176. |
Pitch angle scattering of charged particles by MHD waves. |

177. |
Nonlinear evolution of relativistic ring instability. |

178. |
Acceleration of charged particles by nonlinear MHD waves. |

179. |
Pitch angle diffusion of charged particles by MHD waves. |

180. |
Multiscale reconnection in the magnetotail. |

181. |
Multi-fluid modeling of quasi-perpendicular shock waves. |

182. |
Nonlinear evolution of electromagnetic instabilities driven by a relativistic ring distribution. |

183. |
Jeans instability in a dusty plasma: hybrid simulation studies. |

184. |
Comparison between the Landau and cyclotron resonances in the electron beam-plasma interactions. |

185. |
Langevin modeling of the magnetotail. |

186. |
Acceleration of charged particles by large amplitude MHD waves: effect of wave spatial correlation. |

187. |
Acceleration of charged particles by large amplitude MHD waves: soliton acceleration model. |

188. |
Multi-fluid modeling of quasi-perpendicular shocks. |

189. |
Acceleration of Charged Particles by Large Amplitude MHD Waves: Trapping of Particels by an Alfven wave. |

190. |
Decay instabiliry of a large amplitude electrmagnetic cyclotron wave in a relativistic electron-positron plasma. |

191. |
Plasma maser instability in a turbulent plasma. |

192. |
Cross field transport of cosmic rays. |

193. |
Long time nonlinear evolution of electromagnetic waves driven by a relativistic ring distribution. |

194. |
Acceleration of charged particles by MHD waves with finite spatial coherence. |

195. |
Langevin modelling of multiple magnetic reconnections. |

196. |
Plasma Jeans instability in the interstellar medium. |

197. |
Nonlinear evolution of dust condensation in a plasma and stellar formation. |

198. |
Self-organization via multiple magnetic reconnections. |

199. |
Thermal convection in the forced Swift-Hohenberg model. |

200. |
Nonlinear waves and turbulence in space plasmas. |

201. |
Acceleration of Charged Particles by Spatially Correlated MHD Waves. |

202. |
Anomalous Energy Diffusion of Charged Particles by Large Amplitude MHD Waves. |

203. |
Relativistic parametric instabilities of large amplitude Alfven waves. |

204. |
Nonlinear evolution of electromagnetic waves driven by the relativistic ring distribution. |

205. |
Lengevin modeling of the magnetotail. |

206. |
Transverse stability of localized MHD structures. |

207. |
Nonlinear evolution of plasma Jeans instability. |

208. |
Acceleration of Energetic Particles by Nonlinear MHD Waves. |

209. |
Transverse Stability of Localized MHD Structures. |