Precise calculation of the magnetosphere surface for a tilted dipole

Observations at the planet Mercury by the Plasma Electron Experiment: Mariner 10

“…We interprkt this as evidence that the spacecraft potential with respect to the plasma is some 40 eV (see, e.g., Montgomery, 1913); within the polar low flux region the spacecraft potential appears`to increase up to 90-100 eV; no such In Figure 9 we show two_.determinations of the average magnetopause and bow shock boundary shapes for the case of the Earth; obtained by empirical fits to a large number of observed boundary crossings, using magnetometer data from five Explorer spacecraft (Fairfield,-1971) The observed magnetopause crossings can also be compared with a theoretical magnetopause surface we have used that calculated by Choe, Beard, and Sullivan (1973). Each observed crossing then defines a value of S and a corresponding value of rSP ; these are listed in Table III.…”

Inter-hemispheric asymmetry of dependence of the cusp location on dipole tilt during northward IMF conditions

“…This will result in some different effect of the solar radiation on the two hemispheres. Choe et al (1973) predicted the dipole tilt angle effect by a simple magnetic dipole model plus magnetopause current. It has also been found that the dayside field-aligned currents (FACs) move poleward and equatorward in the summer and winter hemispheres, respectively (Fujii et al, 1981;Christiansen et al, 2002;Ohtani et al, 2005).…”

“…It has been theoretically predicted that the cusp would be several degrees lower in the hemisphere whose dipole axis pointed away from the solar wind ram velocity direction (Choe et al, 1973). Based on the OGO4 data (700 km of altitude), Burch (1972) first investigated the effect of dipole tilt angle on the cusp equatorward boundary and found a cusp shifted by approximately 4 • in the invariant latitude (ILAT) over the total yearly range of dipole tilt angles.…”

Space Weather

“…First, most spacecraft or bital planes which cross the magnetopause lie close to the ecliptic plane, so the higher latitude magnetopause (where PETRINEC 261 the cusps regions are located) is not often sampled. Second, a surface which includes the cusps can be very complicated, and is probably not well modeled with a simple conic sec tion (cf., Choe et al, 1973). Third, spacecraft magneto pause data sets contain a limited number of magnetopause crossings.…”