A new, temporarily confined population in the polar cap during the August 27, 1996 geomagnetic field distortion period

Chen, Jiasheng; Fritz, T. A.; Sheldon, Robert B.; Spence, H. E.; Spjeldvik, W. N.; Fennell, J. F.; Livi, S.

doi:10.1029/97gl01369

Cited by 88 publications

(62 citation statements)

References 15 publications

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“…These CDC's are also reported to exhibit enhanced plasma thermal pressure and density, as well as turbulent magnetic fluctuations (Savin et al, 1998;Le et al, 2001;Savin et al, 2002Savin et al, , 2004Nykyri et al, 2004Nykyri et al, , 2006. Cusp energetic particles (CEP's) of up to at least 2 MeV were first reported in the high altitude polar cusp region by Chen et al in 1996(Chen et al, 1997. The energization mechanism however, remains a topic of significant debate Chang et al, 1998).…”

Section: Introductionmentioning

confidence: 99%

3-D mesoscale MHD simulations of a cusp-like magnetic configuration: method and first results

2011

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Abstract. We present a local mesoscale model of the magnetospheric cusp region with high resolution (up to 300 km). We discuss the construction and implementation of the initial configuration and give a detailed description of the numerical simulation. An overview of simulation results for the case of strongly northward interplanetary magnetic field (IMF) is then presented and compared with data from Cluster 2 spacecraft from 14 February 2003. Results show a cusp diamagnetic cavity (CDC) with depth normal to the magnetospheric boundary on the order of 1-2 R E and a much larger extent of ∼5-9 R E tangential to the boundary, bounded by a gradual inner boundary with the magnetospheric lobe and a more distinct exterior boundary with the magnetosheath. These results are qualitatively consistent with observational data.

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Section: Introductionmentioning

confidence: 99%

3-D mesoscale MHD simulations of a cusp-like magnetic configuration: method and first results

2011

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“…Observations from a number of spacecraft have shown the presence of energetic particles in the magnetospheric cusp (Shelly et al, 1976;Kremser et al, 1995;Chen et al, 1997;Pfaff et al, 1998;Savin et al, 2002); however, their source remains a matter of scientific discussion and debate. The polar cusp region, where these particles are observed, is idenCorrespondence to: B. M. Walsh (bwalsh@bu.edu) tified by a minimum local magnetic field (Ferrell and Van Allen, 1990) and an increased magnetosheath plasma (Frank, 1971).…”

Section: Introductionmentioning

confidence: 99%

“…Cusp Energetic Particle (CEP) events are characterized by a decreased and turbulent local magnetic field, as well as increased energetic particle flux (Chen et al, 1997(Chen et al, , 1998Fritz et al, 1999). During these events, electrons show large flux enhancements for 100 eV particles and more subtle flux enhancements up to 200 keV.…”

Section: Introductionmentioning

confidence: 99%

Energetic particles observed by ISEE-1 and ISEE-2 in a cusp diamagnetic cavity on 29 September 1978

et al. 2007

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Abstract.Observations by the ISEE-1 and ISEE-2 spacecraft on 29 September 1978 show large CEP (Cusp Energetic Particle) fluxes while passing through the dayside magnetospheric cusp in near coincident orbits. The event was observed around 11:00 MLT between roughly 12:30 and 13:00 UT by ISEE-1 and 12:00 and 13:00 UT by ISEE-2. During these periods, both electron and ion fluxes increased by more than two orders of magnitude, with the electron flux showing a strong peak at a pitch angle of 90 • . The solar wind was ∼710 km s −1 and the Dst was ∼-200 nT, suggesting the occurrence of a strong geomagnetic storm. The ISEE-1 and ISEE-2 observations, however, show no time-energy dispersion of the CEPs, leading us to believe that these particles could not be the result of substorm processes in the magnetotail. The local magnetic field was depressed and extremely turbulent. Changes in the magnitude of the magnetic field anticorrelate closely to variations of the electron flux. The observations in electron flux peaking at 90 • and the close anticorrelation between the local magnetic field strength and electron flux are unique and provide evidence of a potential local source for these energetic particles.

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“…More recent in situ measurements in the high-altitude dayside cusp from the Polar spacecraft identified cusp diamagnetic cavities (CDCs) defined by a depressed and turbulent magnetic field (Chen et al, 1997. Large intensities of cusp energetic particles (CEPs) with energies up to 8 MeV are also shown to be present within the CDCs.…”

Section: Introductionmentioning

confidence: 99%

Properties of a cusp diamagnetic cavity boundary

2008

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Abstract. While crossing through the high-altitude dayside cusp on 29 September 1978 and again on 30 October 1978, the ISEE-1 spacecraft observed enhanced energetic particle flux and a depressed and turbulent magnetic field, the signature characteristics of a cusp diamagnetic cavity. As ISEE-1 approached the cavity during each event, a boundary sounding technique was used to measure properties of an emitting boundary. Sounding over multiple energy channels reveals an energy dependent boundary with lower energy particles filling a larger cavity than higher energy particles. Relative motion of the boundary as well as boundary orientation are also measured. The two cusp events were measured at different locations and during different geomagnetic and solar wind conditions; however, they show similar results.

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A new, temporarily confined population in the polar cap during the August 27, 1996 geomagnetic field distortion period

Cited by 88 publications

References 15 publications

3-D mesoscale MHD simulations of a cusp-like magnetic configuration: method and first results

3-D mesoscale MHD simulations of a cusp-like magnetic configuration: method and first results

Energetic particles observed by ISEE-1 and ISEE-2 in a cusp diamagnetic cavity on 29 September 1978

Properties of a cusp diamagnetic cavity boundary

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