CAWSES (Climate And Weather of the Sun-Earth System) Space Weather Database in Japan Observation (CAWSESDB-J-SM0014) Version 1.0 March 2007 (CAWSES SPACE-W Database in Japan) Ion beam instabilities in space plasmas

SM0014

Introduction
The database contains simulation runs of ion beam instabilities as typically found in space plasmas. These instabilities play important roles in the energy transfer and dissipation in space plasmas. Nonlinear evolutions of these instabilities are reproduced by one-dimensional particle simulation with periodic boundaries. All computations were performed on the KEMPO1/MATLAB software. The database includes several kinds of plots showing detailed processes of nonlinear evolution of ion beam instability. The left upper and right upper panels are scatter plots of the particles in the velocity of phase space X-Vx and X-Vy, respectively. The left bottom panel is velocity distribution function f (Vx). The right bottom panel is scatter plot of particles in the 3 dimensional phase space Vx-Vy-Vz.

1. EMIC R-mode instability driven by an ion beam

The low frequency part of the whistler mode wave at a long wavelength is called an R-mode electromagnetic ion cyclotron wave (EMIC), which can be excited by an ion beam with a drift velocity satisfying the anomalous cyclotron resonance condition.

2. EMIC L-mode instability driven by a temperature anisotropy

L-mode ion cyclotron waves are excited through the cyclotron instability driven by energetic ions with temperature anisotropy as R-mode whistler mode waves are excited by anisotropic energetic electrons.

3. EMIC L-mode instability with heavily ions

The L-mode EMIC waves with heaviliy ions are presented. The L-mode dispersion is split into two branches because of the cyclotron resonance with the heavy ions.

4. Ion Bernstein instability

When we assume a cold ring distribution in the velocity phase space with a small thermal velocity, there arises an instability with the wave vector perpendicular to the static magnetic field. If we analyze the frequency spectra, we find diffused electron Bernstein modes at harmonics of the electron cyclotron frequency (WC = -10) not only in the electrostatic component Ex but also in the electromagnetic component Ez and Bz. Since the ion cyclotron frequency is 0.4, we need to enlarge the low frequency range. Using the zooming function of the MATLAB figure, we can study fine structures in the low frequency range of the w-k diagram. Strong electrostatic and electromagnetic components are excited at harmonics of the ion cyclotron frequency. These are ion Bernstein modes.

5. Ion acoustic instability

When the temperature of electrons is much larger than that of ions, the ion acoustic waves can propagate in the plasma without damping. By injecting a cold ion beam into such a plasma, we can excite a two-stream ion instability.

All computations were performed on the KEMPO1/MATLAB software.

Appendix A. KEMPO1 Software

The basic concept and techniques of the one-dimensional electromagnetic particle code:KEMPO1 [Omura and Matsumoto, 1993] are reviewed briefly. Special characteristics of the code are enhanced electrostatic thermal fluctuations that often interfere the physical processes to be reproduced in the particle code. From a simplified analysis on the fluctuations, a criteria for the grid spacing is given. A modification of the KEMPO1 for solution of the relativistic equation of motion is also described. Since the essential part of the code is very simple and short, the KEMPO1 code is implemented with the MATLAB software, using the powerful graphic library. Explanation of the input parameters for the relativistic KEMPO1/MATLAB code and several examples of the applications are given.

System requirements:
Microsoft Windows XP, 2000
Up to 300MB of available hard-disk space

All current details concerning KEMPO1 on MATLAB can be seen on the following webpage. KEMPO1 Official Site :
http://www.rish.kyoto-u.ac.jp/isss7/KEMPO/

Appendix B. How to see figures

If MATLAB(R) are already installed on your PC, you just click links to see figures.

Other than the above, you can see figures using the KEMPO1 software. Run the KEMPO1, go to "File -> Fig. View" and select the file ".fig" from the DVD-ROM.

Contact: 
Yoshiharu  Omura and Koichi Shin
Research Institute for Sustainable Humanosphere,
Kyoto University
Gokasho, Uji, 611-0011, Japan
Phone:  +81-774-38-3811
E-mail:  omura[AT]rish.kyoto-u.ac.jp   

Acknowledgments:
Support for the production of this CAWSES Space Weather International Collaborative Research (CAWSES SPACE-W) Database in Japan was provided by the Grant-in-Aid for Publication of Scientific Research Results, the Grant-in-Aid for Scientific Research (KAKENHI) from Japan Society for the Promotion of Science (JSPS).