Articles | Volume 15, issue 5
Nonlin. Processes Geophys., 15, 773–782, 2008
https://doi.org/10.5194/npg-15-773-2008
Nonlin. Processes Geophys., 15, 773–782, 2008
https://doi.org/10.5194/npg-15-773-2008

  22 Oct 2008

22 Oct 2008

Mitigation of energetic electrons in the magnetosphere by amplified whistler wave under double cyclotron resonances

S. P. Kuo S. P. Kuo
  • Department of Electrical and Computer Engineering, Polytechnic Institute of New York University, 6 MetroTech Center, Brooklyn, NY 11201, USA

Abstract. An optimal approach reducing the population of MeV electrons in the magnetosphere is presented. Under a double resonance condition, whistler wave is simultaneously in cyclotron resonance with keV and MeV electrons. The injected whistler waves is first amplified by the background keV electrons via loss-cone negative mass instability to become effective in precipitating MeV electrons via cyclotron resonance elevated chaotic scattering. The numerical results show that a small amplitude whistler wave can be amplified by more than 25 dB. The amplification factor reduces only about 10 dB with a 30 dB increase of the initial wave intensity. Use of an amplified whistler wave to scatter 1.5 MeV electrons from an initial pitch angle of 86.5°to a pitch angle <50° is demonstrated. The ratio of the required wave magnetic field to the background magnetic field is calculated to be about 8×10−4.