A comparison of predictions of an MHD model solar wind flow past the magnetopause with AMPTE/IRM observations on 24 October, 1985
We compare numerical results of a steady-state MHD model for solar wind flow past the terrestrial magnetosphere with documented observations made by the AMPTE/IRM spacecraft on 24 October, 1985, during an inbound crossing of the magnetosheath. Observations indicate that steady conditions prevail during this ∼ 4 hour-long crossing. The magnetic shear at entry into the magnetosphere was 15 deg. A steady density decrease and a concomitant magnetic field pile-up were observed during the ∼ 40 min interval just preceding the magnetopause crossing. In this so-called plasma depletion layer (i) the plasma beta fell generally below unity; (ii) the flow speed tangential to the magnetopause was enhanced; and (iii) the local magnetic field and velocity vectors became increasingly more orthogonal to each other as the magnetopause was approached (Phan et al., 1994). We model parameter variations along a orbit similar to the AMPTE/IRM trajectory, which was at slightly southerly latitudes and ∼ 1.5 hours post-noon local time (GSE). In our model we consider the magnetopause to be a tangential discontinuity, as suggested by the observations, and take as input solar wind parameters those measured by AMPTE/IRM just prior to its bow shock crossing. We find that theoretical predictions match all observations closely.
Advances in Space Research
Digital Object Identifier (DOI)
Farrugia, CJ; Biernat, HK; Erkaev, NV; Kistler, LM (1998). A comparison of predictions of an MHD model solar wind flow past the magnetopause with AMPTE/IRM observations on 24 October, 1985, SOLAR-TERRESTRIAL RELATIONS: PREDICTING THE EFFECTS ON THE NEAR- EARTH ENVIRONMENT. Vol. 22, No. 1, 67-72. DOI: 10.1016/S0273-1177(97)01102-2