The Interplanetary Magnetic Field: Its Effects on the Solar Wind Flow

Abstract. We present a new reconstruction of the interplanetary magnetic field (IMF, B) for 1846–2012 with a full analysis of errors, based on the homogeneously constructed IDV(1d) composite of geomagnetic activity presented in Part 1 (Lockwood et al., 2013a). Analysis of the dependence of the commonly used geomagnetic indices on solar wind parameters is presented which helps explain why annual means of interdiurnal range data, such as the new composite, depend only on the IMF with only a very weak influence of the solar wind flow speed. The best results are obtained using a polynomial (rather than a linear) fit of the form B = χ · (IDV(1d) − β)α with best-fit coefficients χ = 3.469, β = 1.393 nT, and α = 0.420. The results are contrasted with the reconstruction of the IMF since 1835 by Svalgaard and Cliver (2010).

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MHD effects of the solar wind flow around planets

Nonlinear Processes in Geophysics ◽

10.5194/npg-7-201-2000 ◽

2000 ◽

Vol 7 (3/4) ◽

pp. 201-210 ◽

Cited By ~ 2

Author(s):

H. K. Biernat ◽

N. V. Erkaev ◽

C. J. Farrugia ◽

D. F. Vogl ◽

W. Schaffenberger

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Mach Number ◽

Boundary Conditions ◽

Wind Flow ◽

Magnetic Shear ◽

Thermal Anisotropy ◽

Terrestrial Magnetosphere ◽

Solar Wind Flow

Abstract. The study of the interaction of the solar wind with magnetized and unmagnetized planets forms a central topic of space research. Focussing on planetary magnetosheaths, we review some major developments in this field. Magnetosheath structures depend crucially on the orientation of the interplanetary magnetic field, the solar wind Alfvén Mach number, the shape of the obstacle (axisymmetric/non-axisymmetric, etc.), the boundary conditions at the magnetopause (low/high magnetic shear), and the degree of thermal anisotropy of the plasma. We illustrate the cases of Earth, Jupiter and Venus. The terrestrial magnetosphere is axisymmetric and has been probed in-situ by many spacecraft. Jupiter's magnetosphere is highly non-axisymmetric. Furthermore, we study magnetohydrodynamic effects in the Venus magnetosheath.

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Investigation of the magnetic field between the shock wave and the obstacle in the solar wind flow around a planet

Advances in Space Research ◽

10.1016/0273-1177(81)90092-2 ◽

1981 ◽

Vol 1 (1) ◽

pp. 101-104

Author(s):

V.B. Boranov ◽

E.G. Eroshenko ◽

M.D. Kartalev ◽

I.P. Mastikov

Keyword(s):

Magnetic Field ◽

Shock Wave ◽

Solar Wind ◽

Wind Flow ◽

Solar Wind Flow ◽

The Magnetic Field

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An optimization principle for computing stationary MHD equilibria with solar wind flow

10.5194/egusphere-egu2020-3029 ◽

2020 ◽

Author(s):

Thomas Wiegelmann ◽

Thomas Neukirch ◽

Dieter Nickeler ◽

Iulia Chifu

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Coronal Magnetic Field ◽

Field Vector ◽

Source Surface ◽

Solar Chromosphere ◽

Wind Flow ◽

Solar Wind Flow ◽

Nonlinear Force ◽

The Magnetic Field

Knowledge about the magnetic field and plasma environment is important for almost all physical processes in the solar atmosphere. Precise measurements of the magnetic field vector are done routinely only in the photosphere, e.g. by SDO/HMI. These measurements are used as boundary condition for modelling the solar chromosphere and corona, whereas some model assumptions have to be made. In the low-plasma-beta corona the Lorentz-force vanishes and the magnetic field is reconstructed with a nonlinear force-free model. In the mixed-beta chromosphere plasma forces have to be taken into account with the help of a magnetostatic model. And finally for modelling the global corona far beyond the source surface the solar wind flow has to be incorporated within a stationary MHD model. To do so, we generalize a nonlinear force-free and magneto-static optimization code by the inclusion of a field aligned compressible plasma flow. Applications are the implementation of the solar wind on global scale. This allows to reconstruct the coronal magnetic field further outwards than with potential field, nonlinear force-free and magneto-static models. This way the model might help in future to provide the magnetic connectivity for joint observations of remote sensing and in-situ instruments on Solar Orbiter and Parker Solar Probe.

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Waves in the magnetic field and solar wind flow outside the bow shock at comet P/Halley

Exploration of Halley’s Comet ◽

10.1007/978-3-642-82971-0_7 ◽

1988 ◽

pp. 47-54 ◽

Cited By ~ 1

Author(s):

A. Johnstone ◽

K. Glassmeier ◽

M. Acuna ◽

H. Borg ◽

D. Bryant ◽

...

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Bow Shock ◽

Wind Flow ◽

Solar Wind Flow ◽

The Magnetic Field

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Modelling the evolution of CMEs and their shocks through different solar wind structures

10.5194/egusphere-egu2020-11003 ◽

2020 ◽

Author(s):

Erika Palmerio ◽

Christina Lee ◽

Leila Mays ◽

Dusan Odstrcil

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Vantage Point ◽

Angular Width ◽

Wind Flow ◽

The Sun ◽

Ambient Wind ◽

Fast Wind ◽

Solar Wind Flow ◽

Ambient Solar Wind

The evolution of coronal mass ejections (CMEs) as they travel away from the Sun is one of the major issues in heliophysics and space weather. After erupting, CMEs propagate outwards through the background solar wind flow, which in turn may significantly affect CME evolution by means of e.g. acceleration, deflection, and/or rotation. In order to determine to which extent the ambient wind can alter the speed, trajectory, and orientation of a CME, we run a series of 3D magnetohydrodynamics simulations (using the coupled solar&#8211;heliospheric WSA&#8211;Enlil model) to conduct a multi-vantage point study of the radial and longitudinal evolution of CME structures as they propagate up to Earth&#8217;s (1 AU) and Mars&#8217; (1.5 AU) orbits. We explore a broad range of input CME parameters (initial radial speed, angular width) and ambient solar wind conditions (slow versus fast wind) to investigate the different evolutionary behaviours of CMEs and their driven shocks and sheath regions. To study the radial and longitudinal evolution for the modelled CME ejecta and shock events, we examine the resulting magnetic field and plasma time series at different heliocentric distances (0.5 AU, 1 AU, and 1.5 AU) and heliolongitudes (in 30&#176; increments). This work will help establish a set of expected CME behaviours at Earth&#8217;s and Mars&#8217; radial distances, which can be used for analysing real CME events.

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ULF waves in the foreshock formed by the radial IMF: their effect on solar wind sheath-like deflection

10.5194/egusphere-egu2020-3687 ◽

2020 ◽

Author(s):

Olga Gutynska ◽

Jaroslav Urbář ◽

Jana Šafránková ◽

Zdeněk Němeček

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Statistical Study ◽

Low Frequency ◽

Bow Shock ◽

Ulf Waves ◽

Wind Flow ◽

Solar Wind Flow ◽

The Mean

Particle reflection at the bow shock provides a source of free energy to drive local instabilities and turbulence within the foreshock. A variety of low-frequency fluctuations (up to 16 mHz) results from the interactions of back-streaming ions with the incoming solar wind flow. We report observations of low-frequency magnetosonic waves observed during intervals of a radial interplanetary magnetic field in the foreshock. A case study of simultaneous dual THEMIS spacecraft observations of asymmetrical fluctuations in Vy is complemented by a statistical study of similar solar wind deflections in the foreshock.&#160; Our moment calculations do not include the reflected particles as well as heavier ions, revealed the modulation of a solar wind core and deflection of the solar wind in the foreshock. This effect decreases with the distance from the bow shock. We conclude that large asymmetrical Vy velocity component fluctuations are typical for the foreshock formed by the radial IMF. The asymmetry of fluctuations changes the mean direction of the incoming solar wind flow within the foreshock leading to preconditioning prior to its encounter with the bow shock.

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