Inner radiation belt electron lifetimes due to whistler‐induced electron precipitation (WEP) driven losses

Rodger, Craig J.; Clilverd, Mark A.

doi:10.1029/2002gl015795

Cited by 18 publications

(21 citation statements)

References 16 publications

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“…Recently, Green et al [2005] suggested lightning to be an embryonic source of hiss due to the geographic (preference over land masses) and local time (stronger in the afternoon sector) characteristics that are consistent with properties of lightning [ Christian et al , 2003]. Observations of radiation belt losses due to LEP [ Voss et al , 1998; Blake et al , 2001; Rodger and Clilverd , 2002] suggest that LEP may be an important loss mechanism at lower energies. Theoretical estimates have suggested that LEP might be a significant contributor to electron loss at mid‐latitudes [ Abel and Thorne , 1998], but experimental evidence of such a global role has been lacking.…”

Section: Introductionmentioning

confidence: 99%

Seasonal dependence of energetic electron precipitation: Evidence for a global role of lightning

Gemelos

Inan

Walt

et al. 2009

Geophysical Research Letters

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Analysis of the DEMETER spacecraft particle data shows that energetic electron precipitation exhibits a seasonal dependence consistent with lighting‐induced electron precipitation (LEP). Over the United States, energetic electron fluxes in the slot region (between L = 2 and 3) are significantly higher in the northern summer than in the winter, consistent with the seasonal variation of lightning activity in the Northern Hemisphere. The association of precipitating fluxes with lightning is explored using lightning location data from the National Lightning Detection Network (NLDN) and VLF wave data on DEMETER. The increased precipitation of particles into the drift loss cone over the Northern Hemisphere in summer is consistent with expected pitch‐angle scattering by lightning‐generated whistler waves, indicating that lightning is a significant contributor to the loss of slot region electrons.

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Section: Introductionmentioning

confidence: 99%

Seasonal dependence of energetic electron precipitation: Evidence for a global role of lightning

Gemelos

Inan

Walt

et al. 2009

Geophysical Research Letters

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“…Combining reports of satellite LEP observations with ground‐based precipitation occurrence frequency measurements, Rodger et al [2003] argued for typical LEP mean precipitation energy flux of 2 × 10 −3 ergs cm −2 s −1 (or 0.002% of the trapped flux), concluding that in some electron energy ranges LEP may be the most significant inner radiation belt loss process. Rodger and Clilverd [2002] also investigated the impact of precipitation from the radiation belts globally by combining cloud‐ground lightning flash rates at midlatitudes with the effects from a typical LEP event. The precipitation from the radiation belts modifies the lower ionosphere reflection height over altitudes of ∼75–92 km, with ionization changes of a factor of 10–12 occurring at times [ Rodger et al , 2002].…”

Section: Introductionmentioning

confidence: 99%

Radiation belt electron precipitation fluxes associated with lightning

2004

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[1] In this study we consider the dependence of precipitation fluxes arising from whistler-induced radiation belt losses on the strength of the associated lightning's return stroke current. As a result of this work, it will be possible to use lightning activity data sets to estimate globally induced precipitation flux rates and thus determine the lightning-induced effect on the radiation belts more accurately. Four study days were selected, during which a high proportion of the lightning activity occurring near the east coast of North America produced observable Trimpi effects on VLF transmitter signals propagating in the region of the Antarctic Peninsula ($L = 2-2.5). The lack of lightning in Antarctica gives this location a unique advantage for this study. The functional dependence of the relative scattered field amplitude with the return stroke peak current of the lightning discharge suggests that during these events diffusion conditions are occurring near the precipitating radiation belt particles loss cone due to strong whistler wave fields, probably caused by ducted signals. The range of observed Trimpi scatter amplitude of À10 to À35 dB was produced by precipitation bursts with energy fluxes estimated to range over 6.5-0.4 Â 10 À3 ergs cm À2 s À1 . The largest fluxes were found to be driven by lightning currents of about 250 kA, while the smallest detectable fluxes relate to lightning currents of 70 kA. Although 3 of the 4 study days showed a high degree of consistency between the levels of lightning return stroke peak current required to produce any given perturbation scatter amplitude value, conditions were significantly different on 23 April 1994. On this day, observed Trimpi signatures were 6-7 dB greater for any given lightning intensity than on the other study days. These events are consistent with a significantly harder radiation belt precipitation spectra, probably caused by geomagnetic storm-time acceleration processes of radiation belt electrons.

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“…However, during major geomagnetic storms, such as the Halloween storm in 2003, the flux of relativistic electrons in the slot region increases dramatically [Baker et al, 2004], as a result of enhanced inward transport and wave acceleration Shprits et al, 2006;Thorne et al, 2007]. The enhanced flux of relativistic electrons subsequently decay to the prestorm equilibrium levels on a timescale of days to weeks, largely due to the resonant pitch angle scattering by plasmaspheric hiss [Lyons et al, 1972;Lyons and Thorne, 1973;Albert, 1994;Thorne 1998a, 1998b], although losses due to lightning-induced electron precipitation may be important at lower energies [Voss et al, 1998;Blake et al, 2001;Rodger and Clilverd, 2002]. Farther out, pitch angle scattering by plasmaspheric hiss contributes to the loss of outer radiation belt electrons during the main and recovery phases of a storm [Summers et al, 2007] and can explain the quiet time decay of outer radiation belt electrons over a wide range of energies and L shells [e.g., Meredith et al, 2006a].…”

Section: Introductionmentioning

confidence: 99%

Slot region electron loss timescales due to plasmaspheric hiss and lightning‐generated whistlers

et al. 2007

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[1] Energetic electrons (E > 100 keV) in the Earth's radiation belts undergo Dopplershifted cyclotron resonant interactions with a variety of whistler mode waves leading to pitch angle scattering and subsequent loss to the atmosphere. In this study we assess the relative importance of plasmaspheric hiss and lightning-generated whistlers in the slot region and beyond. Electron loss timescales are determined using the Pitch Angle and energy Diffusion of Ions and Electrons (PADIE) code with global models of the spectral distributions of the wave power based on CRRES observations. Our results show that plasmaspheric hiss propagating at small and intermediate wave normal angles is a significant scattering agent in the slot region and beyond. In contrast, plasmaspheric hiss propagating at large wave normal angles and lightning-generated whistlers do not contribute significantly to radiation belt loss. The loss timescale of 2 MeV electrons due to plasmaspheric hiss propagating at small and intermediate wave normal angles in the center of the slot region (L = 2.5) lies in the range 1-10 days, consistent with recent Solar Anomalous and Magnetospheric Particle Explorer (SAMPEX) observations. Wave turbulence in space, which is responsible for the generation plasmaspheric hiss, thus leads to the formation of the slot region. During active periods, losses due to plasmaspheric hiss may occur on a timescale of 1 day or less for a wide range of energies, 200 keV < E < 1 MeV, in the region 3.5 < L < 4.0. Plasmaspheric hiss may thus also be a significant loss process in the inner region of the outer radiation belt during magnetically disturbed periods.Citation: Meredith, N. P., R. B. Horne, S. A. Glauert, and R. R. Anderson (2007), Slot region electron loss timescales due to plasmaspheric hiss and lightning-generated whistlers,

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Inner radiation belt electron lifetimes due to whistler‐induced electron precipitation (WEP) driven losses

Cited by 18 publications

References 16 publications

Seasonal dependence of energetic electron precipitation: Evidence for a global role of lightning

Seasonal dependence of energetic electron precipitation: Evidence for a global role of lightning

Radiation belt electron precipitation fluxes associated with lightning

Slot region electron loss timescales due to plasmaspheric hiss and lightning‐generated whistlers

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