2007年12月
Ultra-relativistic acceleration of electrons in planetary magnetospheres
GEOPHYSICAL RESEARCH LETTERS
- ,
- 巻
- 34
- 号
- 24
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1029/2007GL032226
- 出版者・発行元
- AMER GEOPHYSICAL UNION
We present a new particle acceleration mechanism called ultra-relativistic acceleration (URA). URA comprises electron energization due to a special form of nonlinear phase trapping by a coherent whistler-mode wave for electrons with an initial Lorentz factor gamma(0) satisfying gamma(0) > Omega(EQ)/omega; omega is the wave frequency and Omega(EQ) is the electron cyclotron frequency at the equator of an assumed dipole magnetic field. Radiation belt electrons that encounter a combination of relativistic turning acceleration (RTA) followed by multiple URA interactions can undergo significant energy increase. Under ideal conditions, at Earth (L = 4) several-hundred-keV electrons can be energized to several MeV within a few seconds, while at Jupiter (L = 8), several-hundred-keV electrons can be energized by tens of MeV in a few tens of seconds. URA can play a prominent role in generating the several- MeV electrons observed in Earth's outer zone and the tens-of-MeV electrons observed in Jupiter's magnetosphere. More generally, we expect URA to be an effective electron energization mechanism in cosmic plasma environments that contain a magnetic mirror geometry and electromagnetic whistler-mode emissions.
- リンク情報
- ID情報
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- DOI : 10.1029/2007GL032226
- ISSN : 0094-8276
- eISSN : 1944-8007
- Web of Science ID : WOS:000252012700007