scholarly journals Gyromagnetic Emission and Absorption: Approximate Formulas of Wide Validity

1984 ◽  
Vol 37 (6) ◽  
pp. 675 ◽  
Author(s):  
PA Robinson ◽  
DB Melrose
Keyword(s):  
Pitch Angle ◽  
Bessel Functions ◽  
Harmonic Number ◽  
Relativistic Electrons ◽  
Angle Distribution ◽  
Pitch Angle Distribution ◽  
Approximate Formulas

Approximate formulas of wide validity are derived for gyro magnetic emission and absorption of gyromagnetic waves by mildly relativistic electrons. An averaged emissivity is defined by replacing the sum over harmonic number by an integral and averaging over the pitch angle distribution of the radiating particles. A method for performing the average over pitch angle without approximation to the Bessel functions is developed and the resulting expressions are then approximated using Wild-Hill formulas which interpolate between the non-relativistic and ultra-relativistic limits.

scholarly journals Pitch angle distribution of relativistic electrons in the inner radiation belt and its relation to equatorial plasma wave turbulence phenomena

2001 ◽  
Vol 28 (5) ◽  
pp. 931-934 ◽  
Author(s):  
Akira Morioka ◽  
Hiroaki Misawa ◽  
Yoshizumi Miyoshi ◽  
Hiroshi Oya ◽  
Masahide Iizima ◽  
...  
Keyword(s):  
Plasma Wave ◽  
Pitch Angle ◽  
Radiation Belt ◽  
Wave Turbulence ◽  
Relativistic Electrons ◽  
Angle Distribution ◽  
Pitch Angle Distribution

scholarly journals Peculiar pitch angle distribution of relativistic electrons in the inner radiation belt and slot region

2014 ◽  
Vol 41 (7) ◽  
pp. 2250-2257 ◽  
Author(s):  
H. Zhao ◽  
X. Li ◽  
J. B. Blake ◽  
J. F. Fennell ◽  
S. G. Claudepierre ◽  
...  
Keyword(s):  
Pitch Angle ◽  
Radiation Belt ◽  
Relativistic Electrons ◽  
Angle Distribution ◽  
Pitch Angle Distribution

scholarly journals Comparison between CNA and energetic electron precipitation: simultaneous observation by Poker Flat Imaging Riometer and NOAA satellite

2005 ◽  
Vol 23 (5) ◽  
pp. 1555-1563 ◽  
Author(s):  
Y.-M. Tanaka ◽  
M. Ishii ◽  
Y. Murayama ◽  
M. Kubota ◽  
H. Mori ◽  
...  
Keyword(s):  
Pitch Angle ◽  
Electron Flux ◽  
Energetic Electron ◽  
Energetic Particles ◽  
Electron Precipitation ◽  
Angle Distribution ◽  
Pitch Angle Distribution ◽  
Loss Cone ◽  
Isotropic Pitch ◽  
Trapped Electron

Abstract. The cosmic noise absorption (CNA) is compared with the precipitating electron flux for 19 events observed in the morning sector, using the high-resolution data obtained during the conjugate observations with the imaging riometer at Poker Flat Research Range (PFRR; 65.11° N, 147.42° W), Alaska, and the low-altitude satellite, NOAA 12. We estimate the CNA, using the precipitating electron flux measured by NOAA 12, based on a theoretical model assuming an isotropic pitch angle distribution, and quantitatively compare them with the observed CNA. Focusing on the eight events with a range of variation larger than 0.4dB, three events show high correlation between the observed and estimated CNA (correlation coefficient (r0)>0.7) and five events show low correlation (r0<0.5). The estimated CNA is often smaller than the observed CNA (72% of all data for 19 events), which appears to be the main reason for the low-correlation events. We examine the assumption of isotropic pitch angle distribution by using the trapped electron flux measured at 80° zenith angle. It is shown that the CNA estimated from the trapped electron flux, assuming an isotropic pitch angle distribution, is highly correlated with the observed CNA and is often overestimated (87% of all data). The underestimate (overestimate) of CNA derived from the precipitating (trapped) electron flux can be interpreted in terms of the anisotropic pitch angle distribution similar to the loss cone distribution. These results indicate that the CNA observed with the riometer may be quantitatively explained with a model based on energetic electron precipitation, provided that the pitch angle distribution and the loss cone angle of the electrons are taken into account. Keywords. Energetic particles, precipitating – Energetic particles, trapped – Ionosphere-magnetosphere interactions

The Pitch Angles of Electrons in Jupiter’s Radiation Belt

1976 ◽  
Vol 3 (1) ◽  
pp. 53-55 ◽  
Author(s):  
J. A. Roberts
Keyword(s):  
Radio Emission ◽  
Pitch Angle ◽  
Radiation Belt ◽  
Synchrotron Emission ◽  
Angle Distribution ◽  
Space Probe ◽  
Frequency Range ◽  
Pitch Angle Distribution ◽  
5 Ghz ◽  
Apparent Conflict

The radio emission from Jupiter in the frequency range from ∽ 50 MHz to ∽ 5 GHz is mainly synchrotron emission from electrons in the intense radiation belt which surrounds Jupiter out to several planetary radii. Information about the pitch angles of these electrons can be derived both from the radio observations and from the Pioneer space probe observations. In this communication we discuss the pitch angle distribution inferred from the radio data and the apparent conflict with the Pioneer data.

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