Found 3 results
Filters: Author is J. B. Blake  [Clear All Filters]
Authors: Turner D L, O'Brien T. P., Fennell J F, Claudepierre S. G., Blake J. B., et al.
Title: Investigating the source of near-relativistic and relativistic electrons in Earth's inner radiation belt
Abstract: Using observations from NASA's Van Allen Probes, we study the role of sudden particle enhancements at low L shells (SPELLS) as a source of inner radiation belt electrons. SPELLS events are characterized by electron intensity enhancements of approximately an order of magnitude or more in less than 1 day at L < 3. During quiet and average geomagnetic conditions, the phase space density radial distributions for fixed first and second adiabatic invariants are peaked at 2 < L < 3 for electrons ranging in energy from ~50 keV to ~1 MeV, indicating that slow inward radial diffusion is not the dominant source of inner belt electrons under quiet/average conditions. During SPELLS events, the evolution of electron distributions reveals an enhancement of phase space density that can e. . .
Date: 01/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/1999JA900445 Available at:
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Authors: O’Brien T P, Looper M. D., and Blake J. B.
Title: Quantification of relativistic electron microburst losses during the GEM storms
Abstract: Bursty precipitation of relativistic electrons has been implicated as a major loss process during magnetic storms. One type of precipitation, microbursts, appears to contain enough electrons to empty the prestorm outer radiation belt in approximately a day. During storms that result in high fluxes of trapped relativistic electrons, microbursts continue for several days into the recovery phase, when trapped fluxes are dramatically increasing. The present study shows that this apparent inconsistency is resolved by observations that the number of electrons lost through microbursts is 10–100 times larger during the main phase than during the recovery phase of several magnetic storms chosen by the Geospace Environment Modeling (GEM) program.
Date: 02/2004 Publisher: Geophysical Research Letters DOI: 10.1029/2003GL018621 Available at:
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Authors: O’Brien T P, Lorentzen K. R., Mann I. R., Meredith N. P., Blake J. B., et al.
Title: Energization of relativistic electrons in the presence of ULF power and MeV microbursts: Evidence for dual ULF and VLF acceleration
Abstract: We examine signatures of two types of waves that may be involved in the acceleration of energetic electrons in Earth's outer radiation belts. We have compiled a database of ULF wave power from SAMNET and IMAGE ground magnetometer stations for 1987–2001. Long-duration, comprehensive, in situ VLF/ELF chorus wave observations are not available, so we infer chorus wave activity from low-altitude SAMPEX observations of MeV electron microbursts for 1996–2001 since microbursts are thought to be caused by interactions between chorus and trapped electrons. We compare the ULF and microburst observations to in situ trapped electrons observed by high-altitude satellites from 1989–2001. We find that electron acceleration at low L shells is closely associated with both ULF activity and MeV microbu. . .
Date: 08/2003 Publisher: Journal of Geophysical Research DOI: 10.1029/2002JA009784 Available at:
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