Magnetospheric response to the solar wind as indicated by the cross-polar potential drop and the low-latitude asymmetric disturbance field

Eriksson, S.; Blomberg, Lars G.; Ivchenko, Nickolay; Karlsson, Tomas; Marklund, Göran

doi:10.5194/angeo-19-649-2001

Cited by 4 publications

(4 citation statements)

References 22 publications

(42 reference statements)

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“…Other MHD simulations may produce larger JH levels, but they also clearly overestimate the cross-polar potential drop. The cross-polar potential drop has also been calculated from the same Astrid-2/EMMA database than what is used in this study and was found to be in good agreement with other studies (Eriksson et al, 2001).…”

Section: Introductionsupporting

confidence: 86%

Statistics of Joule heating in the auroral zone and polar cap using Astrid-2 satellite Poynting flux

et al. 2004

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Abstract. We make a statistical study of ionospheric Joule heating with the Poynting flux method using six months of Astrid-2/EMMA electric and magnetic field data during 1999 (solar maximum year). For the background magnetic field we use the IGRF model. Our results are in agreement with earlier statistical satellite studies using both the P E 2 method and the Poynting flux method. We present a rather comprehensive set of fitted Joule heating formulas expressing the Joule heating in given magnetic local time (MLT) and invariant latitude (ILAT) range under given solar illumination conditions as a function of the K p index, the AE index, the Akasofu epsilon parameter and the solar wind kinetic energy flux. The study thus provides improved and more detailed estimates of the statistical Joule heating. Such estimates are necessary building blocks for future quantitative studies of the power budget in the magnetosphere and in the nightside auroral region.

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Section: Introductionsupporting

confidence: 86%

Statistics of Joule heating in the auroral zone and polar cap using Astrid-2 satellite Poynting flux

et al. 2004

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“…The third timescale is the duration of the growth phase after which AL decreases rapidly and the nightside reconnection voltage is enhanced. As well as being seen in flow responses detected by radars and magnetometers [e.g., Grocott et al, 2002], these timescales have been detected in transpolar voltage data [e.g., Eriksson et al, 2001].…”

Section: Introductionmentioning

confidence: 85%

“…[38] Several studies report a dependence of transpolar voltage on the dawn-to-dusk interplanetary motional electric field using a form such as V sw Bsin 4 (q/2) [e.g., Eriksson et al, 2001]. In addition several statistical fits have introduced Figure 7.…”

Section: Analysis In Terms Of the Expandingcontracting Polar Cap Modelmentioning

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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“…EMMA has provided new and valuable data that may deepen our understanding of the interaction mechanisms (e.g. Eriksson et al, 2001). …”

Section: Scientific Objectives and Resultsmentioning

confidence: 99%

EMMA - the Electric and Magnetic Monitor of the Aurora on Astrid-2

et al. 2004

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Abstract. The Astrid-2 mission has dual primary objectives. First, it is an orbiting instrument platform for studying auroral electrodynamics. Second, it is a technology demonstration of the feasibility of using micro-satellites for innovative space plasma physics research. The EMMA instrument, which we discuss in the present paper, is designed to provide simultaneous sampling of two electric and three magnetic field components up to about 1 kHz. The spin plane components of the electric field are measured by two pairs of opposing probes extended by wire booms with a separation distance of 6.7 m. The probes have titanium nitride (TiN) surfaces, which has proved to be a material with excellent properties for providing good electrical contact between probe and plasma. The wire booms are of a new design in which the booms in the stowed position are wound around the exterior of the spacecraft body. The boom system was flown for the first time on this mission and worked flawlessly. The magnetic field is measured by a tri-axial fluxgate sensor located at the tip of a rigid, hinged boom extended along the spacecraft spin axis and facing away from the Sun. The new advanced-design fluxgate magnetometer uses digital signal processors for detection and feedback, thereby reducing the analogue circuitry to a minimum. The instrument characteristics as well as a brief review of the science accomplished and planned are presented.

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Magnetospheric response to the solar wind as indicated by the cross-polar potential drop and the low-latitude asymmetric disturbance field

Cited by 4 publications

References 22 publications

Statistics of Joule heating in the auroral zone and polar cap using Astrid-2 satellite Poynting flux

Statistics of Joule heating in the auroral zone and polar cap using Astrid-2 satellite Poynting flux

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

EMMA - the Electric and Magnetic Monitor of the Aurora on Astrid-2

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