Whistler mode noise in Jupiter's inner magnetosphere

Journal Article · Sat Jul 01 00:00:00 EDT 1978 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA083iA07p03151· OSTI ID:6673813

Sentman, D D; Goertz, C K

The distinctive 'hat shape' of equatorial pitch angle distributions constructed from Pioneer 10 and 11 Jupiter observations of energetic electrons E/sub e/>21 MeV and E/sub e/>31 MeV at L=3 is examined from the point of view of pitch angle diffusion by resonant interaction with a band-limited spectrum of whistler mode noise. In this picture, the pitch angle profiles are consistent with whistler mode noise limited to frequencies below an upper cutoff frequency 2.8< or approx. =..integral../sub c/< or approx. =4.6kHz. Equatorial linear growth 3<10 using previously published models for the spatial distribution of thermal plasma and the energetic electron distributions. The maximum frequency for which wave growth is positive at L=3 is roughly consistent with that implied by the 21- and 31-MeV equatorial pitch angle profiles. Maximum growth rates computed from the respective energetic electron models span the range 0.1< or approx. =..gamma../sub max/< or approx. =10 s/sup -1/ throughout the inner region. The spectral extent of the whistler mode noise, defined by those frequencies for which ..gamma..>0.5..gamma../sub max,/ is approximately 2--10 kHz a L=3 and falls smoothly to 0.2--2 kHz at L =10. Raytracing of nonducted whistlers of characteristic frequencies 1-4 kHz generated at the magnetic equator and propagated through a finite temperature (100--400 eV) hydrogen plasma cengrifugally confined near the magnetic equatorial plane shows that wave phase speed decrease to near or below electron thermal speeds before high-latitude reflection can occur. Wave growth in this case is limited to a disclike region centered about the magnetic equator. The amplitude growth of the most unsable whistlers propagating across the growth region parallel to the magnetic field is approx.exp (3--4).

• Research Organization: Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242
• OSTI ID: 6673813
• Journal Information: J. Geophys. Res.; (United States), Vol. 83:A7
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
JUPITER PLANET
PLANETARY MAGNETOSPHERES
DIFFUSION
ELECTRON SPECTRA
INCLINATION
WHISTLERS
ATMOSPHERES
ELECTROMAGNETIC RADIATION
NOISE
PLANETARY ATMOSPHERES
PLANETS
RADIATIONS
RADIO NOISE
RADIOWAVE RADIATION
SPECTRA
640107* - Astrophysics &amp; Cosmology- Planetary Phenomena