IMF control of the Earth's magnetosphere

Nishida, A.

doi:10.1007/bf00194626

Cited by 41 publications

(22 citation statements)

References 12 publications

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“…[2] Many publications over many years have demonstrated the relationship between ionospheric transpolar voltage and the electric field (as measured in the Earth's frame of reference) in the interplanetary medium impinging on the magnetosphere [Reiff et al, 1981;Cowley, 1981Cowley, , 1984Doyle and Burke, 1983;Nishida, 1983;Wygant et al, 1983;Reiff et al, 1985;Reiff and Luhmann, 1986;Ahn et al, 1992;Boyle et al, 1997;Hairston et al, 1998;Lu et al, 2002aLu et al, , 2002bPapitashvili and Rich, 2002;Shepherd et al, 2002;Bristow et al, 2004;Nakata et al, 2004;Hairston et al, 2005;Ridley, 2005;Ruohoniemi and Greenwald, 2005;Zhang et al, 2007]. These studies, either explicitly or implicitly, assumed steady state conditions because the ionospheric flow pattern and voltage are studied as a function of the prevailing conditions (interplanetary or geomagnetic) with no allowance made for the prior history of those conditions [Lockwood, 1991].…”

Section: Introductionmentioning

confidence: 99%

Transpolar voltage and polar cap flux during the substorm cycle and steady convection events

et al. 2009

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[1] Transpolar voltages observed during traversals of the polar cap by the Defense Meteorological Satellite Program (DMSP) F-13 spacecraft during 2001 are analyzed using the expanding-contracting polar cap model of ionospheric convection. Each of the 10,216 passes is classified by its substorm phase or as a steady convection event (SCE) by inspection of the AE indices. For all phases, we detect a contribution to the transpolar voltage by reconnection in both the dayside magnetopause and in the crosstail current sheet. Detection of the IMF influence is 97% certain during quiet intervals and >99% certain during substorm/SCE growth phases but falls to 75% in substorm expansion phases: It is only 27% during SCEs. Detection of the influence of the nightside voltage is only 19% certain during growth phases, rising during expansion phases to a peak of 96% in recovery phases: During SCEs, it is >99%. The voltage during SCEs is dominated by the nightside, not the dayside, reconnection. On average, substorm expansion phases halt the growth phase rise in polar cap flux rather than reversing it. The main destruction of the excess open flux takes place during the 6-to 10-hour interval after the recovery phase (as seen in AE) and at a rate which is relatively independent of polar cap flux because the NENL has by then retreated to the far tail. The best estimate of the voltage associated with viscous-like transfer of closed field lines into the tail is around 10 kV.

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Section: Introductionmentioning

confidence: 99%

Transpolar voltage and polar cap flux during the substorm cycle and steady convection events

et al. 2009

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“…Space weather basically begins with this interaction. Studies have shown that the interplanetary magnetic field (IMF) strongly controls the state of the magnetosphere (Nishida, 1983). While the solar wind pressure can determine the size of the magnetosphere, less is understood about how the pressure influences the electrodynamics of the magnetosphere-ionosphere system.…”

Section: Introductionmentioning

confidence: 99%

The response of the magnetosphere-ionosphere system to a sudden dynamic pressure enhancement under southward IMF conditions

Ridley

2009

Ann. Geophys.

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Abstract.The magnetospheric response to step-like solar wind dynamic pressure increases under southward IMF conditions is studied using the University of Michigan MHD code. A two phased response in the ionosphere is observed, similar to what is observed when the IMF is northward by looking into the residual potential and field-aligned current (FAC) patterns in the ionosphere. The first phase response right after the high pressure enhancement hits the magnetopause is associated with a pair of FACs downward in the postnoon and upward in the prenoon region. These FACs are caused by dusk-to-dawn electric fields inside the dayside magnetopause launched by a fast mode compressional wave. The second phase response shows another pair of potential cells as well as FACs in opposite polarity, which originates from magnetospheric vortices on the equatorial plane. The vortices appear to be formed by the recovery of the system from the fast mode wave.

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“…During periods of southward directed interplanetary magnetic field, when the solar wind energy can be directly coupled to the magnetosphere, the role of the cross tail current sheet has been recognized as fundamental in energy storage, plasma energetization andmagnetic fieldreconftguration (e.g., McPherron, 1972;Russell and McPherron, 1973;Lui, 1978;Sauvaud and Winckler, 1980;Nishida, 1983;Fairfield, 1984;Kaufmann, 1987;Lui et al, 1992).…”

Section: Introductionmentioning

confidence: 99%

Large Scale Dynamics of the Magnetospheric Tail Induced by Substorms: A Multisatellite Study

Sauvaud¹,

Jacquey²,

Beutier³

et al. 1996

J. geomagn. geoelec

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The large scale dynamics ofthe tail during substorms are examinedusing multi-satellite measurements made between 18 and 22:00 UT on August 22, 1983. We use data from ISEEI/2, 1977-007, IMP-8, and ISEE-3 located in the solar wind or tail at distances along the Sun-Earth line ranging from +11 to -205RE. During the period studied, which corresponded to a southward directed IMF, successive plasma injections were detected at 6.6RE first during a general increase of the magnetic field in the lobe. The magnetic field increase is attributed to an enhanced reconnection rate, as evidenced by the close relationship between the tail lobe magnetic energy density and the available Poynting energy in the solar wind, for near constant solar wind pressure. A Traveling Compression Region (flux rope) was detected in close association with the first energetic particle injection at geostationary orbit. After the first injections, the series of injections continued and the last ones are shown to be linked with a tailward propagating cross-tail current disruption detected onboard IMP-8 at --35RE. This event is seen in the distant tail at 205RE onboard ISEE-3 as an increase of the tail radius; the far magnetosphere engulfed the ISEE-3 satellite which was located in the solar wind prior to the event. The characteristic time delay between cross-tail current disruption onset occurring in the near-Earth plasma sheet and the enhancement of the tail diameter at 205RE is on the order of 40 minutes. Several hours before this event, a similar case was detected in which partial cross-tail current disruption in the mid-tail was also related to a far tail expansion. In both cases, the observed signatures are in agreement with the concept of the ejection of plasmoids from the magnetospheric tail with velocities comparable to that of the solarwind. These results strongly suggest that traveling cross-tail current disruption and plasmoid ejection from the far tail are the signature of the same propagating plasma process.

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IMF control of the Earth's magnetosphere

Cited by 41 publications

References 12 publications

Transpolar voltage and polar cap flux during the substorm cycle and steady convection events

Transpolar voltage and polar cap flux during the substorm cycle and steady convection events

The response of the magnetosphere-ionosphere system to a sudden dynamic pressure enhancement under southward IMF conditions

Large Scale Dynamics of the Magnetospheric Tail Induced by Substorms: A Multisatellite Study

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