scholarly journals The pitch angle distribution transition of energetic particles at substorm onset observed by GEOS-2

2000 ◽  
Vol 27 (5) ◽  
pp. 645-648 ◽  
Author(s):  
Z. X. Chen ◽  
A. Korth ◽  
Z. Y. Pu ◽  
C. Mouikis
Keyword(s):  
Pitch Angle ◽  
Energetic Particles ◽  
Substorm Onset ◽  
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

scholarly journals Reconnection and energetic particles at the edge of the exterior cusp

2006 ◽  
Vol 24 (7) ◽  
pp. 1949-1956 ◽  
Author(s):  
T. Asikainen ◽  
K. Mursula
Keyword(s):  
Magnetic Field ◽  
Pitch Angle ◽  
Energetic Particles ◽  
Maximum Energy ◽  
Closed Field ◽  
Angle Distribution ◽  
Pitch Angle Distribution ◽  
Flux Transfer Events ◽  
Cusp Region ◽  
Field Lines

Abstract. In this paper we study flux transfer events (FTE) observed at the post-noon edge of the exterior cusp region by Cluster satellites. During the outbound dayside orbit on 2 February 2003, intense bursts of energetic particles were observed in close conjuction with magnetic field FTE signatures by the RAPID instrument onboard the Cluster 4. The pitch-angle distribution of the particles showed that the enhancements consist of particles flowing antiparallel to the magnetosheath field lines away from the expected reconnection site to the exterior cusp. At the same time Cluster 3 observed enhancements of energetic particles deeper in the exterior cusp with a delay of about 40 s to the Cluster 4 enhancements. The estimated maximum energy gain per particle by reconnection remains below 1 keV, thus clearly below the tens to hundreds of keV energy range observed by the RAPID instrument. These observations support the earlier statistical result of the magnetospheric origin of energetic particles in the exterior cusp. Reconnection near the exterior cusp partly releases the particles in the closed field lines of the adjacent HLPS region into the exterior cusp.

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.

scholarly journals Solar cosmic rays by the ground level observation: anisotropy

2019 ◽  
Vol 127 ◽  
pp. 02027
Author(s):  
Yury Balabin ◽  
Aleksei Germanenko ◽  
Boris Gvozdevsky
Keyword(s):  
Inverse Problem ◽  
Cosmic Rays ◽  
Pitch Angle ◽  
Ground Level ◽  
Problem Solution ◽  
Angle Distribution ◽  
Pitch Angle Distribution ◽  
Solar Cosmic Rays ◽  
Inverse Problem Solution ◽  
Distribution Form

Nine large GLE events have been studied by the improved methodic of the inverse problem solution. The problems of the SCR anisotropy form setting have been in detail worked out in the new methodic. The SCR pitch-angle distribution form is automatically selected in solution search. It significantly improves the solutions convergence.

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