Combined first and second order Fermi acceleration at comets

T. I. Gombosi, K. Lorencz, J. Randy Jokipii

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Our two-dimensional, time-dependent model calculations indicate that an interplay between velocity and spatial diffusion may be responsible for the acceleration of implanted heavy ions in the cometary preshock region. Velocity diffusion (second order Fermi acceleration) accelerates the pickup ions to moderate energies thus creating a seed population for the more efficient diffusive-compressive shock acceleration. Solar wind convection limits the time available for diffusive-compressive acceleration, therefore the resulting energy spectrum above 100 keV is a power law with a spectral index of 5 - 6, a value which is in reasonably good agreement with observations.

Original languageEnglish (US)
Pages (from-to)337-341
Number of pages5
JournalAdvances in Space Research
Volume9
Issue number3
DOIs
StatePublished - 1989

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comets
comet
Solar wind
ion
Pickups
Heavy ions
solar wind
energy
Seed
seeds
heavy ions
power law
energy spectra
convection
shock
seed
sensors
Ions
ions

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Combined first and second order Fermi acceleration at comets. / Gombosi, T. I.; Lorencz, K.; Jokipii, J. Randy.

In: Advances in Space Research, Vol. 9, No. 3, 1989, p. 337-341.

Research output: Contribution to journalArticle

Gombosi, T. I. ; Lorencz, K. ; Jokipii, J. Randy. / Combined first and second order Fermi acceleration at comets. In: Advances in Space Research. 1989 ; Vol. 9, No. 3. pp. 337-341.
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