Solar wind interaction with the Earth's magnetic field: 2. Magnetohydrodynamic bow shock

The magnetosphere is the region where cosmic rays and the solar wind interact with the Earth's magnetic field, creating such phenomena as the northern lights and other aurorae. The configuration and dynamics of the magnetosphere are of interest to planetary physicists, geophysicists, plasma astrophysicists, and to scientists planning space missions. The circulation of solar wind plasma in the magnetosphere and substorms have long been used as the principle paradigms for studying this vital region. Charles F. Kennel, a leading scientist in the field, here presents a synthesis of the convection and substorm literatures, and an analysis of convection and substorm interactions; he also suggests that the currently accepted steady reconnection model may be advantageously replaced by a model of multiple tail reconnection events, in which many mutually interdependent reconnections occur. Written in an accessible, non-mathematical style, this book introduces the reader to the exciting discoveries in this fast-growing field.

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Energetic protons at Mars: interpretation of SLED/Phobos-2 observations by a kinetic model

Annales Geophysicae ◽

10.5194/angeo-30-1595-2012 ◽

2012 ◽

Vol 30 (11) ◽

pp. 1595-1609 ◽

Cited By ~ 5

Author(s):

E. Kallio ◽

S. McKenna-Lawlor ◽

M. Alho ◽

R. Jarvinen ◽

S. Dyadechkin ◽

...

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Kinetic Model ◽

Energetic Particle ◽

Particle Energy ◽

Bow Shock ◽

Solar Wind Interaction ◽

Flux Enhancement ◽

Field Environment ◽

Electric And Magnetic Fields

Abstract. Mars has neither a significant global intrinsic magnetic field nor a dense atmosphere. Therefore, solar energetic particles (SEPs) from the Sun can penetrate close to the planet (under some circumstances reaching the surface). On 13 March 1989 the SLED instrument aboard the Phobos-2 spacecraft recorded the presence of SEPs near Mars while traversing a circular orbit (at 2.8 RM). In the present study the response of the Martian plasma environment to SEP impingement on 13 March was simulated using a kinetic model. The electric and magnetic fields were derived using a 3-D self-consistent hybrid model (HYB-Mars) where ions are modelled as particles while electrons form a massless charge neutralizing fluid. The case study shows that the model successfully reproduced several of the observed features of the in situ observations: (1) a flux enhancement near the inbound bow shock, (2) the formation of a magnetic shadow where the energetic particle flux was decreased relative to its solar wind values, (3) the energy dependency of the flux enhancement near the bow shock and (4) how the size of the magnetic shadow depends on the incident particle energy. Overall, it is demonstrated that the Martian magnetic field environment resulting from the Mars–solar wind interaction significantly modulated the Martian energetic particle environment.

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PLASMA TURBULENCE RESULTING FROM THE INTERACTION BETWEEN THE SOLAR WIND AND THE EARTH'S MAGNETIC FIELD

Turbulence and Nonlinear Dynamics in MHD Flows ◽

10.1016/b978-0-444-87396-5.50010-9 ◽

1989 ◽

pp. 55-68

Author(s):

Alain ROUX

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Plasma Turbulence ◽

Earth’S Magnetic Field ◽

Earth's Magnetic Field

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Ultra-low frequency foreshock waves at Venus and Mercury in a global hybrid simulation

10.5194/epsc2020-202 ◽

2020 ◽

Author(s):

Riku Jarvinen ◽

Esa Kallio ◽

Tuija I. Pulkkinen

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Large Scale ◽

Low Frequency ◽

Hybrid Simulation ◽

Bow Shock ◽

Upstream Region ◽

Ulf Waves ◽

Solar Wind Interaction ◽

Low Frequency Waves

We study the solar wind interaction with Venus and Mercury in a 3-dimensional global hybrid simulation where ions are treated as particles and electrons are a charge-neutralizing fluid. We concentrate on the formation of large-scale ultra-low frequency (ULF) waves in ion foreshocks and their dependence on the solar wind and interplanetary magnetic field conditions. The ion foreshock forms in the upstream region ahead of the quasi-parallel bow shock, where the angle between the shock normal and the magnetic field is smaller than about 45 degrees. The magnetic connection with the bow shock allows backstreaming of the solar wind ions leading to the formation of the ion foreshock. This kind of beam-plasma configuration is a source of free energy for the excitation of plasma waves. The foreshock ULF waves convect downstream with the solar wind flow and encounter the bow shock. We compare the waves between Venus and Mercury, and analyze the coupling of the ULF waves with the planetary ion acceleration at Venus. References: Jarvinen R., Alho M., Kallio E., Pulkkinen T.I., 2020, Oxygen Ion Escape From Venus Is Modulated by Ultra-Low Frequency Waves, Geophys. Res. Lett., 47, 11, doi:10.1029/2020GL087462 Jarvinen R., Alho M., Kallio E., Pulkkinen T.I., 2020, Ultra-low frequency waves in the ion foreshock of Mercury: A global hybrid modeling study, Mon. Notices Royal Astron. Soc., 491, 3, 4147-4161, doi:10.1093/mnras/stz3257

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On the edge of the foreshock: model-data comparisons

Annales Geophysicae ◽

10.5194/angeo-26-1539-2008 ◽

2008 ◽

Vol 26 (6) ◽

pp. 1539-1544 ◽

Cited By ~ 29

Author(s):

D. G. Sibeck ◽

N. Omidi ◽

I. Dandouras ◽

E. Lucek

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Field Strength ◽

Magnetic Field Strength ◽

Large Amplitude ◽

Bow Shock ◽

Model Data ◽

Solar Wind Interaction ◽

Hybrid Code ◽

Amplitude Density

Abstract. We present the results of a global hybrid code simulation for the solar wind-interaction with the Earth's magnetosphere during an interval of steady radial IMF. The model predicts a foreshock marked by innumerable localized, correlated, and large amplitude, density and magnetic field strength variations, depressed velocities, and enhanced temperatures. The foreshock is bounded by a broad (~0.8 RE) region of enhanced densities, temperatures, and magnetic field strengths that extends far (~8.6 RE) upstream from the bow shock. Flow perturbations within the boundary are directed perpendicular to the boundary, towards the unperturbed solar wind and away from the foreshock. Cluster observations of the ion foreshock and pristine solar wind confirm the predictions of the model. The observations suggest that foreshock cavities, crater-like density and magnetic field strength structures whose cores are filled with suprathermal particles, can be interpreted in terms of transient encounters with the foreshock boundary.

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Low-frequency magnetic field fluctuations in Venus' solar wind interaction region: Venus Express observations

Annales Geophysicae ◽

10.5194/angeo-28-951-2010 ◽

2010 ◽

Vol 28 (4) ◽

pp. 951-967 ◽

Cited By ~ 14

Author(s):

L. Guicking ◽

K.-H. Glassmeier ◽

H.-U. Auster ◽

M. Delva ◽

U. Motschmann ◽

...

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Low Frequency ◽

Interaction Region ◽

Wave Intensity ◽

Bow Shock ◽

Solar Wind Interaction ◽

Frequency Magnetic Field ◽

Field Fluctuations ◽

Wave Properties

Abstract. We investigate wave properties of low-frequency magnetic field fluctuations in Venus' solar wind interaction region based on the measurements made on board the Venus Express spacecraft. The orbit geometry is very suitable to investigate the fluctuations in Venus' low-altitude magnetosheath and mid-magnetotail and provides an opportunity for a comparative study of low-frequency waves at Venus and Mars. The spatial distributions of the wave properties, in particular in the dayside and nightside magnetosheath as well as in the tail and mantle region, are similar to observations at Mars. As both planets do not have a global magnetic field, the interaction process of the solar wind with both planets is similar and leads to similar instabilities and wave structures. We focus on the spatial distribution of the wave intensity of the fluctuating magnetic field and detect an enhancement of the intensity in the dayside magnetosheath and a strong decrease towards the terminator. For a detailed investigation of the intensity distribution we adopt an analytical streamline model to describe the plasma flow around Venus. This allows displaying the evolution of the intensity along different streamlines. It is assumed that the waves are generated in the vicinity of the bow shock and are convected downstream with the turbulent magnetosheath flow. However, neither the different Mach numbers upstream and downstream of the bow shock, nor the variation of the cross sectional area and the flow velocity along the streamlines play probably an important role in order to explain the observed concentration of wave intensity in the dayside magnetosheath and the decay towards the nightside magnetosheath. But, the concept of freely evolving or decaying turbulence is in good qualitative agreement with the observations, as we observe a power law decay of the intensity along the streamlines. The observations support the assumption of wave convection through the magnetosheath, but reveal at the same time that wave sources may not only exist at the bow shock, but also in the magnetosheath.

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