Articles | Volume 15, issue 2
Nonlin. Processes Geophys., 15, 265–273, 2008
https://doi.org/10.5194/npg-15-265-2008
Nonlin. Processes Geophys., 15, 265–273, 2008
https://doi.org/10.5194/npg-15-265-2008

  17 Mar 2008

17 Mar 2008

Nonadiabatic interaction between a charged particle and an MHD pulse

Y. Kuramitsu1 and T. Hada2 Y. Kuramitsu and T. Hada
  • 1Institute of Laser Engineering, Osaka University, Suita, Japan
  • 2ESST, Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga, Japan

Abstract. Interaction between a magnetohydrodynamic~(MHD) pulse and a charged particle is discussed both numerically and theoretically. Charged particles can be accelerated efficiently in the presence of spatially correlated MHD waves, such as short large amplitude magnetic structures, by successive mirror reflection (Fermi process). In order to understand this process, we study the reflection probability of particles by the MHD pulses, focusing on the adiabaticity on the particle motion. When the particle velocity is small (adiabatic regime), the probability that the particle is reflected by the MHD pulse is essentially determined only by the pitch angle, independent from the velocity. On the other hand, in the non-adiabatic regime, the reflection probability is inversely proportional to the square root of the normalized velocity. We discuss our numerical as well as analytical results of the interaction process with various pulse amplitude, pulse shape, and the pulse winding number. The reflection probability is universally represented as a power law function independent from above pulse properties.

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