In:
Journal of Geophysical Research: Space Physics, American Geophysical Union (AGU), Vol. 87, No. A10 ( 1982-10), p. 8174-8190
Abstract:
This work is a continuation of paper 1 (Young et al., 1981) and is devoted to the generation process of ion cyclotron waves (ICWs) and the acceleration of He + ions up to suprathermal energies. Simultaneous measurements are used from the ion composition experiment (0 〈 E 〈 16 keV), the energetic particle experiment (24 〈 E 〈 3 300 keV), and the ULF wave experiment (0.2–10 Hz) on board the GEOS 1 and GEOS 2 spacecraft. General characteristics of the local time distribution of ICWs will be presented and compared with those of the thermal anisotropy of energetic protons and the He + abundance. Further calculations of the convective growth rate are conducted by applying two different methods, both of which are based upon the measured proton fluxes. The generation conditions of the ICWs in the presence of He + ions will be investigated and three possible explanations will be discussed: (1) enhanced convection growth rates, (2) lowering of the threshold for absolute instabilities, and (3) change of the ICWs ray path (laser‐like effect). Finally, it is shown that the flux of suprathermal He + ions is modulated at the ICW frequency. Owing to nonlinear effects, part of the energy of the energetic protons is transfered via the ICWs to the He + ions that are essentially accelerated in the direction perpendicular to the static magnetic field. Then in the otherwise collisionless plasma the friction between energetic anisotropic protons and thermal He + ions is achieved through the ICWs.
Type of Medium:
Online Resource
ISSN:
0148-0227
DOI:
10.1029/JA087iA10p08174
Language:
English
Publisher:
American Geophysical Union (AGU)
Publication Date:
1982
detail.hit.zdb_id:
2033040-6
detail.hit.zdb_id:
3094104-0
detail.hit.zdb_id:
2130824-X
detail.hit.zdb_id:
2016813-5
detail.hit.zdb_id:
2016810-X
detail.hit.zdb_id:
2403298-0
detail.hit.zdb_id:
2016800-7
detail.hit.zdb_id:
161666-3
detail.hit.zdb_id:
161667-5
detail.hit.zdb_id:
2969341-X
detail.hit.zdb_id:
161665-1
detail.hit.zdb_id:
3094268-8
detail.hit.zdb_id:
710256-2
detail.hit.zdb_id:
2016804-4
detail.hit.zdb_id:
3094181-7
detail.hit.zdb_id:
3094219-6
detail.hit.zdb_id:
3094167-2
detail.hit.zdb_id:
2220777-6
detail.hit.zdb_id:
3094197-0
SSG:
16,13
Bookmarklink