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Detailed Reference Information |
Foat, J.E., Lin, R.P., Smith, D.M., Fenrich, F., Millan, R., Roth, I., Lorentzen, K.R., McCarthy, M.P., Parks, G.K. and Treilhou, J.P. (1998). First detection of a terrestrial MeV X-ray burst. Geophysical Research Letters 25: doi: 10.1029/1998GL900134. issn: 0094-8276. |
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We report the first detection of a terrestrial X-ray burst extending up to MeV energies, made by a liquid-nitrogen-cooled germanium detector (~2 keV FWHM resolution) on a high-altitude balloon at 65.5¿ magnetic latitude (L=5.7) in the late afternoon (1815 MLT) during low geomagnetic activity. The burst occurred at 1532-1554 UT on August 20, 1996, and consisted of seven peaks of ~60--90 s duration, spaced by ~100--200 s, with quasi-periodic (~10--20 s) modulation of the peak count rates. The very hard X-ray spectrum extends to the instrumental limit of 1.4 MeV, and is consistent with bremsstrahlung emission from monoenergetic. ~1.7 MeV, precipitating electrons. Since the trapped relativistic electrons showed a steeply falling energy spectrum from 0.6 to 4 MeV (at L=6.6), the precipitation mechanism appears to be highly energy selective. The modulation frequencies suggest scattering of the MeV electrons due to gyro-resonance with Doppler-shifted electromagnetic ion cyclotron waves, but either equatorial proton densities a factor of ~102 higher than typical for the plasmasphere or significant O+ densities would be required. ¿ 1998 American Geophysical Union |
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Abstract |
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Keywords
Magnetospheric Physics, Energetic particles, precipitating, Magnetospheric Physics, Energetic particles, trapped, Ionosphere, Particle precipitation, Magnetospheric Physics, Magnetosphere/ionosphere interactions |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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