Reconnection voltage as a function of IMF clock angle

Fedder, J. A.; Mobarry, Clark; Lyon, J. G.

doi:10.1029/90gl02722

Cited by 38 publications

(20 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For the short mesh, the lowest cross-polar potential that we ever saw was • õ0 kV. That large voltage caused the error in our previous voltage versus angle curve [Fedder et a/.,1991]. The directly comparable voltage for the long-mesh results is reduced to 13 k¾.…”

Section: Discussionmentioning

confidence: 65%

Topological structure of the magnetotail as a function of interplanetary magnetic field direction

Fedder¹,

Lyon²,

Slinker³

et al. 1995

J. Geophys. Res.

Self Cite

127

View full text Add to dashboard Cite

Magnetic reconnection between the interplanetary magnetic field (IMF) and the geomagnetic field is thought to play a major role in the transfer of solar wind momentum and energy to the magnetosphere. As the angle between the IMF and the geomagnetic field is changed at the bow of the magnetosphere, the topological record of the location of the reconnection region should be recorded in the magnetosheath and on the magnetopause along the flanks of the tail, because the super fast flow freezes strong magnetic gradients formed in the bow reconnection regions into the plasma downstream. In this report, we present results from a three‐dimensional, magnetohydrodynamic (MHD), global numerical simulation code for the location of the separatrix between unconnected IMF magnetosheath field lines and reconnected field lines which penetrate the magnetopause and connect to the polar ionosphere. The angle between the IMF direction and the line where the separatrix crosses the magnetopause is shown to be a sensitive function of the IMF clock angle. We also explain how this behavior can be used to derive an approximate relation for the dependence of the cross‐polar voltage on the IMF clock angle. We conclude with a note of caution concerning the importance of physical boundary conditions in magnetoplasma simulations.

show abstract

Section: Discussionmentioning

confidence: 65%

Topological structure of the magnetotail as a function of interplanetary magnetic field direction

Fedder¹,

Lyon²,

Slinker³

et al. 1995

J. Geophys. Res.

Self Cite

127

View full text Add to dashboard Cite

show abstract

“…Between the cusp crossings by the DMSP satellite the IMF B z component became more negative, suggesting a possible cause for the increased rate of reconnection. The average reconnection voltage is known to be dependent on the magnitude of B z (Reiff et al, 1981;Freeman et al, 1993;Fedder et al, 1991). This can occur because the X-line becomes longer or because the reconnection rate increases, or both.…”

Section: Discussionmentioning

confidence: 99%

The dependence of cusp ion signatures on the reconnection rate

Morley

Lockwood

2003

Ann. Geophys.

View full text Add to dashboard Cite

Abstract. The interpretation of structure in cusp ion dispersions is important for helping to understand the temporal and spatial structure of magnetopause reconnection. "Stepped" and "sawtooth" signatures have been shown to be caused by temporal variations in the reconnection rate under the same physical conditions for different satellite trajectories. The present paper shows that even for a single satellite path, a change in the amplitude of any reconnection pulses can alter the observed signature and even turn sawtooth into stepped forms and vice versa. On 20 August 1998, the Defense Meteorological Satellite Program (DMSP) craft F-14 crossed the cusp just to the south of Longyearbyen, returning on the following orbit. The two passes by the DMSP F-14 satellites have very similar trajectories and the open-closed field line boundary (OCB) crossings, as estimated from the SSJ/4 precipitating particle data and Polar UVI images, imply a similarly-shaped polar cap, yet the cusp ion dispersion signatures differ substantially. The cusp crossing at 08:54 UT displays a stepped ion dispersion previously considered to be typical of a meridional pass, whereas the crossing at 10:38 UT is a sawtooth form ion dispersion, previously considered typical of a satellite travelling longitudinally with respect to the OCB. It is shown that this change in dispersed ion signature is likely to be due to a change in the amplitude of the pulses in the reconnection rate, causing the stepped signature. Modelling of the low-energy ion cutoff under different conditions has reproduced the forms of signature observed.

show abstract

“…For the generic northward IMF cases (θ IMF < 90°), on the other hand, the decrease of the two voltages with decreasing θ IMF slows down. V PC seems to approach a finite value as θ IMF goes to zero, which may arise from other coupling processes between the solar wind and the magnetosphere [see Fedder et al , 1991]. The reconnection voltage V R comes from a direct calculation of the reconnection potential along the merging line, so it should be more relevant to the coupling between the solar wind and the magnetosphere.…”

Section: Merging Line and Reconnection Potential Versus Imf Clock Anglementioning

confidence: 99%

Magnetic merging line and reconnection voltage versus IMF clock angle: Results from global MHD simulations

Peng

Wang

et al. 2009

J. Geophys. Res.

View full text Add to dashboard Cite

[1] This paper proposes diagnosis methods to trace the magnetic merging line and to calculate the electric potential along it for Earth's magnetospheric magnetic fields obtained by global magnetohydrodynamic (MHD) simulations of the solar wind-magnetosphereionosphere (SMI) system. The points with minimum magnetic field strength along last closed magnetic field lines and properly selected closed field lines are combined to trace the whole merging line, and the radial ray integration of convectional electric field is used to calculate the electric potential on the merging line. The diagnosis methods are then applied to magnetospheric magnetic fields associated with different interplanetary magnetic field (IMF) clock angles, and a preliminary analysis is presented on the clock angle response of the geometry of the merging line and the associated reconnection voltage. The merging line is found to be similar in geometry to that of the compound field superposed by the Earth's dipole field and the IMF, whereas the reconnection voltage is approximately fitted by sin 3/2 (q IMF /2) for its response to the IMF clock angle q IMF . The ionospheric transpolar potential and the voltage along the polar cap boundary show different dependence from that of the reconnection voltage, so it is not justified to take them as substitutes for the reconnection voltage. The length of the sunward merging line between the two peaks of reconnection potential shows a nonmonotonic variation in response to q IMF , peaked at q IMF = 90°, so it is also not justified to take electric fields along the merging line, however defined they may be, to characterize the total reconnection rate and the coupling strength between the solar wind and the magnetosphere. The reconnection nearby magnetic nulls closest to the subsolar point is found to be negligible, which gives support to the component reconnection hypothesis for dayside reconnection of quasi-steady states of the SMI system.

show abstract

Reconnection voltage as a function of IMF clock angle

Cited by 38 publications

References 28 publications

Topological structure of the magnetotail as a function of interplanetary magnetic field direction

Topological structure of the magnetotail as a function of interplanetary magnetic field direction

The dependence of cusp ion signatures on the reconnection rate

Magnetic merging line and reconnection voltage versus IMF clock angle: Results from global MHD simulations

Contact Info

Product

Resources

About