Journal ArticleDOI
Mhd flow past an obstacle : large-scale flow in the magnetosheath
TLDR
In this article, a time asymptotic method was used to obtain 3D steady-state solutions for the MHD flow past an obstacle and the results indicated the formation of a depletion layer near the obstacle due to the increase of the magnetic field.Abstract:
As a step to the study of the large-scale flow in the magnetosheath, the MHD flow past an obstacle is investigated. A time asymptotic method is used to obtain 3D steady-state solutions. The results indicate the formation of a depletion layer near the obstacle due to the increase of the magnetic field. Along the earth-sun line the plasma density increases first and then decreases from the post bow shock to the magnetopause. The local density maximum in front of the magnetopause may correspond to what was recently observed. When the interplanetary magnetic field direction is tilted from the solar wind flow, the IMF influences the shape of the bow shock as well as the location of the stagnation point at the magnetopause in a way consistent with observation. In addition, the results show the existence of a magnetosheath current in the post parallel-shock region.read more
Citations
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Journal ArticleDOI
The magnetosheath region adjacent to the dayside magnetopause: AMPTE/IRM observations
TL;DR: In this paper, the magnetic shear across the magnetopause has been investigated and the magnetic field in the magnetosheath region adjacent to the dayside magnetosphere has been found to depend strongly on the angle between the magnetoheath magnetic field and the geomagnetic field.
Journal ArticleDOI
Magnetic spectral signatures in the Earth's magnetosheath and plasma depletion layer
TL;DR: In this article, the authors explore the entire range of magnetic spectral signatures observed from the active magnetospheric Particle Tracer Explorers/charge composition Explorer (AMPTE/CCE)spacecraft in the magnetosheath downstream of a quasi-perpendicular shock.
Journal ArticleDOI
Magnetic pulsations from 0.1 to 4.0 Hz and associated plasma properties in the Earth's subsolar magnetosheath and plasma depletion layer
TL;DR: In this article, the magnetic field data acquired during periods of magnetospheric compressions when the spacecraft sampled the magnetosheath are analyzed on the basis of a dynamic spectral analysis covering frequencies 0.1 to 4.0 Hz.
Journal ArticleDOI
Structure of the Dayside Magnetopause for Low Magnetic Shear
TL;DR: In this paper, the authors analyzed 22 AMPTE/IRM satellite passes through the low-latitude magnetopause region for which the magnetic shear, i.e., the field rotation angle on transit from the magnetosheath to the magnetosphere, was less than 30°.
Calculation by a Moment Technique of the Perturbation of the Geomagnetic Field by the Solar Wind.
Abstract: An iterative method is developed by which one can
calculate approximately the boundary of a magnetic field
confined by a plasma. This method consists essentially of
varying an assumed surface until the magnetic multipole
moments of the currents, which would flow on that surface
to balance the plasma pressure, cancel the corresponding
moments of the magnetic sources within the surface. The
method is applied to two problems. For a dipole source of moment M emu in a plasma of
uniform pressure p dynes/cm^2 that does not penetrate the
magnetic field, the approximate equation of the surface
is r = 0.82615 M^(1/3) p^(-1/6)(1-0.120039α^2 - .004180α^4 - .001085α^6 + .000200α^8 - .000597α^(10) + .000326α^(12) - .000094α^(14)) cm, where α is the latitude in radians from the plane normal to M. The surface formed by a cold plasma of density N_0 and pair mass velocity M_t moving past a dipole of moment Me_y with a velocity –U_oe_z extends to infinity downwind. In a coordinate system (x, y, z) centered at the dipole, neutral points, where the surface is parallel to the wind direction, occur at the points (0, ±R_n, .27R_n), and other points on the surface are (0, 0, 1.02R_n), (0, ±2R_n, -∞) and (±1.97R_n, 0, -∞). R_n = 1.0035 (M/(M_tN_oU^2_o)^(-1/2)^(1/3) is about 9 earth radii for the solar wind case.
References
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Journal ArticleDOI
Depletion of solar wind plasma near a planetary boundary
B. J. Zwan,Richard A. Wolf +1 more
TL;DR: In this paper, a mathematical model is presented that describes the squeezing of solar wind plasma out along interplanetary magnetic field lines in the region between the bow shock and the effective planetary boundary (in the case of the earth, the magnetopause).
Calculation by a Moment Technique of the Perturbation of the Geomagnetic Field by the Solar Wind.
Abstract: An iterative method is developed by which one can
calculate approximately the boundary of a magnetic field
confined by a plasma. This method consists essentially of
varying an assumed surface until the magnetic multipole
moments of the currents, which would flow on that surface
to balance the plasma pressure, cancel the corresponding
moments of the magnetic sources within the surface. The
method is applied to two problems. For a dipole source of moment M emu in a plasma of
uniform pressure p dynes/cm^2 that does not penetrate the
magnetic field, the approximate equation of the surface
is r = 0.82615 M^(1/3) p^(-1/6)(1-0.120039α^2 - .004180α^4 - .001085α^6 + .000200α^8 - .000597α^(10) + .000326α^(12) - .000094α^(14)) cm, where α is the latitude in radians from the plane normal to M. The surface formed by a cold plasma of density N_0 and pair mass velocity M_t moving past a dipole of moment Me_y with a velocity –U_oe_z extends to infinity downwind. In a coordinate system (x, y, z) centered at the dipole, neutral points, where the surface is parallel to the wind direction, occur at the points (0, ±R_n, .27R_n), and other points on the surface are (0, 0, 1.02R_n), (0, ±2R_n, -∞) and (±1.97R_n, 0, -∞). R_n = 1.0035 (M/(M_tN_oU^2_o)^(-1/2)^(1/3) is about 9 earth radii for the solar wind case.
Journal ArticleDOI
Calculation by a moment technique of the perturbation of the geomagnetic field by the solar wind
J. E. Midgley,L. Davis +1 more
TL;DR: In this article, an iterative method is developed by which one can calculate approximately the boundary of a magnetic field confined by a plasma, which consists essentially of varying an assumed surface until the magnetic multipole milliseconds of the currents, which would flow on that surface to balance the plasma pressure, cancel the corresponding moments of the magnetic sources within the surface.
Journal ArticleDOI
Initial Pioneer Venus Magnetic Field Results: Dayside Observations
TL;DR: Observations by the Pioneer Venus mangnetometer in the sunlit ionosphere reveal a dynamic ionosphere, very responsive to external solar-wind conditions, and indicates that the solar wind plays a significant role in the physics of the Venus ionosphere.
Journal ArticleDOI
Observations of plasma depletion in the magnetosheath at the dayside magnetopause
TL;DR: In this paper, a set of 17 low-to mid-latitude crossings of the dayside and near-dayside magnetopause were studied, and Imp 6 plasma measurements showed 11 cases of decreases in magnetosheath density just outside the boundary which are consistent with plasma depletion owing to magnetic flux tube compression as the field becomes draped against the magnetosphere.