Particle signature of magnetic flux transfer events at the magnetopause

Daly, P. W.; Williams, D. J.; Russell, C. T.; Keppler, E.

doi:10.1029/ja086ia03p01628

Cited by 84 publications

(46 citation statements)

References 11 publications

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“…2). (A similar relation between the FTE signatures and energetic particles was presented by Daly et al (1981)). The flux levels are closely similar to those observed during the previous hour when the satellite was in the exterior cusp (see Fig.…”

Section: Detailed Observationsmentioning

confidence: 59%

Reconnection and energetic particles at the edge of the exterior cusp

Asikainen

Мурсула

2006

Ann. Geophys.

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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.

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Section: Detailed Observationsmentioning

confidence: 59%

Reconnection and energetic particles at the edge of the exterior cusp

Asikainen

Мурсула

2006

Ann. Geophys.

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“…Plasma populations originating from the magnetosphere and with a field-aligned anisotropy were first observed inside magnetosheath FTEs by Daly et al (1981), consistent with the spacecraft being on open, reconnected magnetic field lines. A parallel beam observed on open magnetic field lines in the magnetosheath implies a connection to the Southern Hemisphere, whereas an antiparallel beam implies connection to the Northern Hemisphere.…”

Section: Introductionmentioning

confidence: 72%

Motion of flux transfer events: a test of the Cooling model

et al. 2007

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Abstract. The simple model of reconnected field line motion developed by Cooling et al. (2001) has been used in several recent case studies to explain the motion of flux transfer events across the magnetopause. We examine 213 FTEs observed by all four Cluster spacecraft under a variety of IMF conditions between November 2002 and June 2003, when the spacecraft tetrahedron separation was ∼5000 km. Observed velocities were calculated from multi-spacecraft timing analysis, and compared with the velocities predicted by the Cooling model in order to check the validity of the model. After excluding three categories of FTEs (events with poorly defined velocities, a significant velocity component out of the magnetopause surface, or a scale size of less than 5000 km), we were left with a sample of 118 events. 78% of these events were consistent in both direction of motion and speed with one of the two model de Hoffmann-Teller (dHT) velocities calculated from the Cooling model (to within 30 • and a factor of two in the speed). We also examined the plasma signatures of several magnetosheath FTEs; the electron signatures confirm the hemisphere of connection indicated by the model in most cases. This indicates that although the model is a simple one, it is a useful tool for identifying the source regions of FTEs.

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“…Paschmann et al (1982) also observed a bipolar B N signature when the reconnected flux tube was crossed; this was explained by a helicity which was added to the Elphic (1978, 1979) flux tube model by Sonnerup (1987). Field-aligned plasma populations originating from the opposite side of the magnetopause have been observed within FTEs (Daly et al, 1981;Paschmann et al, 1982) consistent with reconnection. The latter study noted the following "essential" features observed in all low-latitude FTEs: a southward component in the undisturbed magnetosheath magnetic field (negative B L ); a bipolar variation in B N ; an enhanced magnetic field strength |B| and an imbalance in the total pressure (p gas +B 2 /2µ 0 ) within both the flux tube and the draping region, countered by the tension in the draped magnetospheric/magnetosheath field lines.…”

Section: Introductionmentioning

confidence: 78%

Cluster observations of bounday layer structure and a flux transfer event near the cusp

et al. 2005

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Abstract. On the 25th January 2002 between 10:00 and 12:00 UT, the four Cluster spacecraft passed through the northern high-latitude cusp, the dayside magnetosphere and into the magnetosheath in a linear formation. In the magnetosphere the PEACE electron spectrometers on the four spacecraft all observed a series of transient bursts of magnetosheath-like plasma, but without bipolar magnetic signatures in the magnetopause normal component as might be expected if the plasma had been injected by transient reconnection (flux transfer events -FTEs). Reordering the data using the magnetopause transition parameter reveals that these plasma observations, the related variations in the magnetic field and the balance of magnetic and thermal gas pressures are consistent with transient entries into a stable highlatitude boundary layer structure. However, once some of the spacecraft entered the magnetosheath, FTE signatures were observed outside the magnetopause at the same time as some of the boundary layer entries occurred at the other spacecraft inside. Thus, (a) the lack of a bipolar B N signature is inconsistent with the traditional picture of a magnetospheric FTE, and (b) the cause of the observed entry of the spacecraft into the boundary layer (pressure pulse or passing magnetosheath FTE) can only be determined by spacecraft observations in the magnetosheath.

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Particle signature of magnetic flux transfer events at the magnetopause

Cited by 84 publications

References 11 publications

Reconnection and energetic particles at the edge of the exterior cusp

Reconnection and energetic particles at the edge of the exterior cusp

Motion of flux transfer events: a test of the Cooling model

Cluster observations of bounday layer structure and a flux transfer event near the cusp

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