Travelling convection vortices in the ionosphere map to the central plasma sheet

Yahnin, A. G.; Moretto, T.

doi:10.1007/s00585-996-1025-3

Cited by 33 publications

(13 citation statements)

References 18 publications

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“…Yahnin and Moretto, 1996) show that events appear to maximise in their magnetic ®eld variations 1±2 o equatorward of the cusp precipitation, and indicate that many TCVs are ®eld-aligned current systems that are evolving very rapidly in space and time. Therefore, some TCVs may be another ionospheric manifestation of the proposed new current system.…”

Section: Implications and Interpretation Of The New Observationsmentioning

confidence: 90%

The ionospheric response to flux transfer events: the first few minutes

Rodger

Pinnock

1997

Ann. Geophys.

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Abstract. We utilise high-time resolution measurements from the PACE HF radar at Halley, Antarctica to explore the evolution of the ionospheric response during the ®rst few minutes after enhanced reconnection occurs at the magnetopause. We show that the plasma velocity increases associated with¯ux transfer events (FTEs) occur ®rst $100±200 km equatorward of the region to which magnetosheath (cusp) precipitation maps to the ionosphere. We suggest that these velocity variations start near the ionospheric footprint of the boundary between open and closed magnetic ®eld lines. We show that these velocity variations have rise times $100 s and fall times of $10 s. When these velocity transients reach the latitude of the cusp precipitation, sometimes the equatorward boundary of the precipitation begins to move equatorward, the expected and previously reported ionospheric signature of enhanced reconnection. A hypothesis is proposed to explain the velocity variations. It involves the rapid out¯ow of magnetospheric electrons into the magnetosheath along the most recently reconnected ®eld lines. Several predictions are made arising from the proposed explanation which could be tested with ground-based and space-based observations.

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Section: Implications and Interpretation Of The New Observationsmentioning

confidence: 90%

The ionospheric response to flux transfer events: the first few minutes

Rodger

Pinnock

1997

Ann. Geophys.

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“…In the recent work of Yahnin et al (1997) and Yahnin and Moretto (1996) it was demonstrated for a few case studies that the position of the centres of the ®eld-aligned currents driving ionospheric travelling convection vortices (TCV) coincide with regions of plasmasheet-type precipitation as identi®ed by particle precipitation data from the DMSP satellites. This result was founded on the Newell scheme (Newell et al, 1991) for the identi®cation of plasma regions.…”

Section: Introductionmentioning

confidence: 99%

Mapping travelling convection vortex events with respect to energetic particle boundaries

Moretto¹,

Yahnin²

1998

Ann. Geophys.

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Abstract. Thirteen events of high-latitude ionospheric travelling convection vortices during very quiet conditions were identi®ed in the Greenland magnetometer data during 1990 and 1991. The latitudes of the vortex centres for these events are compared to the energetic electron trapping boundaries as identi®ed by the particle measurements of the NOAA 10 satellite. In addition, for all events at least one close DMSP overpass was available. All but one of the 13 cases agree to an exceptional degree that: the TCV centres are located within the region of trapped, high energy electrons close to the trapping boundary for the population of electrons with energy greater than b 100 keV. Correspondingly, from the DMSP data they are located within the region of plasmasheet-type precipitation close to the CPS/BPS precipitation boundary. That is, the TCV centres map to deep inside the magnetosphere and not to the magnetopause.

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“…The vortices are typically on the order of 1000 km in extent in the ionosphere and propagate at several km/sec in the anti-sunward direction. TCVs appear to occur on closed field lines, but the mapping of the field to structures such as the magnetopause, the low-latitude boundary layer (LLBL), the boundary of the central plasma sheet, or the CPS itself [Yahnin and Moretto, 1996] is under debate.…”

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confidence: 99%

Response of the ionosphere to a density pulse in the solar wind: Simulation of traveling convection vortices

Slinker¹,

Fedder²,

Hughes³

et al. 1999

Geophysical Research Letters

106

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Abstract.We show the response of the Earth's magnetosphere and ionosphere to a density pulse in the solar wind using a global 3D MHD simulation model. Flow vortices are generated in the ionosphere and they exhibit many properties similar to those observed during impulsive traveling convection vortices. Two oppositely rotating flow vortices are formed at about 70 ø magnetic latitude near noon. They separate and move down the morning and evening flanks, greatly weakening as they pass the terminator. Meanwhile a second pair of flow vortices appears at noon at a slightly higher latitude and with opposite flow directions than the first pair. The second pair follows the first and also fades as it reaches the nightside. The results are interpreted as a hydromagnetic wave propagating in the inhomogeneous magnetosphere plasma.

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Travelling convection vortices in the ionosphere map to the central plasma sheet

Cited by 33 publications

References 18 publications

The ionospheric response to flux transfer events: the first few minutes

The ionospheric response to flux transfer events: the first few minutes

Mapping travelling convection vortex events with respect to energetic particle boundaries

Response of the ionosphere to a density pulse in the solar wind: Simulation of traveling convection vortices

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