Simulated stormtime ring-current magnetic field produced by ions and electrons

Chen, Margaret W.; Schulz, Michael; Liu, Shuxiang; Lu, G.; Lyons, L. R.; El‐Alaoui, M.; Thomsen, Michelle

doi:10.1029/159gm18

Cited by 8 publications

(5 citation statements)

References 17 publications

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“…Plots of the simulated equatorial pressure for electrons, protons, and O + ions at 08:00 UT on 17 March 2013 are shown in Figures a–c. Consistent with previous simulations (Chen, Schulz, Liu, et al, ) and data (Liu et al, ), the electrons contribute the least to the equatorial pressure. The O + ion pressure (Figure c) is fairly weak overall but relatively more intense on the night to dusk side at 08:00 UT, early in the storm main phase.…”

Section: Resultssupporting

confidence: 90%

Diffuse Auroral Electron and Ion Precipitation Effects on RCM‐E Comparisons With Satellite Data During the 17 March 2013 Storm

et al. 2019

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Effects of scattering of electrons from whistler chorus waves and of ions due to field line curvature on diffuse precipitating particle fluxes and ionospheric conductance during the large 17 March 2013 storm are examined using the self-consistent Rice Convection Model Equilibrium (RCM-E) model. Electrons are found to dominate the diffuse precipitating particle integrated energy flux, with large fluxes from~21:00 magnetic local time (MLT) eastward to~11:00 MLT during the storm main phase. Simulated proton and oxygen ion precipitation due to field line curvature scattering is sporadic and localized, occurring where model magnetic field lines are significantly stretched on the night side at equatorial geocentric radial distances r 0 ≳8 R E and/or at r 0~5 .5 to 6.5 R E from dusk to midnight where the partial ring current field has perturbed the magnetic field. The precipitating protons likewise contribute sporadically to the storm time Hall and Pedersen conductance in localized regions whereas the precipitating electrons are the dominate storm time contributor to enhanced Hall and Pedersen conductance at auroral magnetic latitudes on the night and morning side. The RCM-E model can reproduce general features of the Van Allen Probe/MagEIS observed trapped electron differential flux spectrograms over energies of~37 to 150 keV. The simulations with a parameterized electron loss model also reproduce reasonably well the storm time Defense Meteorological Satellite Program integrated electron energy flux at 850 km at satellite crossings from predawn to midmorning. However, model-data agreement is not as good from dusk to premidnight where there are large uncertainties in the electron loss model.

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Section: Resultssupporting

confidence: 90%

Diffuse Auroral Electron and Ion Precipitation Effects on RCM‐E Comparisons With Satellite Data During the 17 March 2013 Storm

et al. 2019

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“…Another interesting feature of the early main phase is the region of the strong current erosion in the noon sector. This erosion, first reported by Tsyganenko and Sitnov [2007] as a general feature of the main phase, is less pronounced in the late main phase (Figure 4d), consistent with simulations of the ring current particle drifts and losses [Chen et al, 2005]. At the same time, it was also detected in the early main phases of other events such as the 27 September 1995, 15 May 1997, 10 March and 26 June 1998 storms.…”

Section: Storm Main Phase Featuressupporting

confidence: 87%

Dynamical data‐based modeling of the storm‐time geomagnetic field with enhanced spatial resolution

et al. 2008

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[1] A new approach, based on an extensible model for the field of equatorial currents and the use of large sets of spacecraft data that became available in recent years, has been shown to dramatically improve the resolution of the empirical picture of the magnetospheric magnetic field. However, accumulation of data, necessary for high resolution in space, may be too long and smear out important dynamical effects. We show that the problem can be resolved using the nearest-neighbor approach, in which the spatial structure of each state of the magnetosphere is described by fitting the empirical model to a local subset of data. It includes both the actual data obtained for the given state and data from other time intervals (e.g., similar phases of other storms), neighboring the present state in the space of global parameters, solar wind electric field, Sym-H index, and its time derivative. New findings in the picture of magnetic storms emerging from the new model include a consistent description of the ring current density peak in the postmidnight sector during the main phase and the premidnight depression of the equatorial magnetic field. The model also shows a strong erosion of the ring current on the dayside during the early main phase and its enhancement in a broad area in the evening sector extending from the geosynchronous orbit to the magnetopause near the Sym-H minimum. Another interesting effect is a double partial ring current during the main phase, consistent with the energy density profiles derived from energetic neutral atom images.

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“…Simulation results from these models generally agree fairly well with in situ particle observations. Recently, Chen et al [2005] calculated the disturbed magnetic field from the simulation results of the storm-time ring current by employing the Biot-Savart law. Their results show that the magnetic field disturbances can be very large in localized regions at L $ 3-5.…”

Section: Introductionmentioning

confidence: 99%

Initial simulation results of storm‐time ring current in a self‐consistent magnetic field model

et al. 2006

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[1] The storm-time ring current generates a strong and time-dependent perturbation of the magnetospheric magnetic fieldB, and this magnetic-field perturbation can have important feedback on the dynamics of ring current particles themselves. In particular, the modification ofB can significantly alter the gradient-curvature drifts of ring current particles, and the induced electric field associated with @B/@t can inhibit ring current particle injection and energization. Thus in order to accurately simulate the storm-time ring current, a self-consistent magnetic field model that takes these effects into account is needed. This study is our first attempt to address this issue. We assume for simplicity a model forB such that magnetic field lines lie in meridional planes and satisfy the generic Dungey field line equation. With these two assumptions and given the pressure distribution in the equatorial plane, the force-balanced magnetic field in the equatorial plane is obtained by solving the force balance equation. This force balance equation solver is coupled with our ring current model to provide self-consistent magnetic fields. In this study, we simulate a hypothetical storm with this magnetically self-consistent ring current model. By comparing our simulation results with statistical studies, we find that our model reasonably reproduces the disturbed magnetic field in the equatorial plane in terms of magnitude and location. The equatorial current density shows an inner eastward ring current at $3 R E , and a outer westward ring current at $4-6.6 R E , which agrees well with observations. The effects of the self-consistent magnetic field on the dynamics of ring-current particles are discussed. We find that the self-consistent magnetic field tends to prevent ring current particles from deep injection and to mitigate the energization of ring current particles. Thus the ring current simulated in a self-consistent magnetic field model will produce less of a disturbance at the center of the Earth than that simulated in the prescribed dipole or dipole-like magnetic field models without feedback from the ring current.

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Simulated stormtime ring-current magnetic field produced by ions and electrons

Cited by 8 publications

References 17 publications

Diffuse Auroral Electron and Ion Precipitation Effects on RCM‐E Comparisons With Satellite Data During the 17 March 2013 Storm

Diffuse Auroral Electron and Ion Precipitation Effects on RCM‐E Comparisons With Satellite Data During the 17 March 2013 Storm

Dynamical data‐based modeling of the storm‐time geomagnetic field with enhanced spatial resolution

Initial simulation results of storm‐time ring current in a self‐consistent magnetic field model

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