Nonthermal ions and associated magnetic field behavior at a quasi-parallel Earth's bow shock

1993 ◽  
Vol 98 (A3) ◽  
pp. 3889-3905 ◽  
Author(s):  
W. P. Wilkinson ◽  
A. K. Pardaens ◽  
S. J. Schwartz ◽  
D. Burgess ◽  
H. Lühr ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Bow Shock ◽  
Field Behavior ◽  
Earth’S Bow Shock

scholarly journals Scattering of field-aligned beam ions upstream of Earth's bow shock

2007 ◽  
Vol 25 (3) ◽  
pp. 785-799 ◽  
Author(s):  
A. Kis ◽  
M. Scholer ◽  
B. Klecker ◽  
H. Kucharek ◽  
E. A. Lucek ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Field Measurements ◽  
Bow Shock ◽  
Ion Distribution ◽  
Parallel Side ◽  
Earth’S Bow Shock ◽  
High Mach ◽  
The Magnetic Field

Abstract. Field-aligned beams are known to originate from the quasi-perpendicular side of the Earth's bow shock, while the diffuse ion population consists of accelerated ions at the quasi-parallel side of the bow shock. The two distinct ion populations show typical characteristics in their velocity space distributions. By using particle and magnetic field measurements from one Cluster spacecraft we present a case study when the two ion populations are observed simultaneously in the foreshock region during a high Mach number, high solar wind velocity event. We present the spatial-temporal evolution of the field-aligned beam ion distribution in front of the Earth's bow shock, focusing on the processes in the deep foreshock region, i.e. on the quasi-parallel side. Our analysis demonstrates that the scattering of field-aligned beam (FAB) ions combined with convection by the solar wind results in the presence of lower-energy, toroidal gyrating ions at positions deeper in the foreshock region which are magnetically connected to the quasi-parallel bow shock. The gyrating ions are superposed onto a higher energy diffuse ion population. It is suggested that the toroidal gyrating ion population observed deep in the foreshock region has its origins in the FAB and that its characteristics are correlated with its distance from the FAB, but is independent on distance to the bow shock along the magnetic field.

scholarly journals Plasma and Magnetic Field Turbulence in the Earth’s Magnetosheath at Ion Scales

2021 ◽  
Vol 7 ◽  
Author(s):  
Liudmila Rakhmanova ◽  
Maria Riazantseva ◽  
Georgy Zastenker
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Solar Wind Plasma ◽  
Bow Shock ◽  
Present Review ◽  
Wind Effects ◽  
Earth’S Bow Shock ◽  
Magnetic Field Turbulence ◽  
Plasma Measurements ◽  
Turbulent Cascade

Crossing the Earth’s bow shock is known to crucially affect solar wind plasma including changes in turbulent cascade. The present review summarizes results of more than 15 years of experimental exploration into magnetosheath turbulence. Great contributions to understanding turbulence development inside the magnetosheath was made by means of recent multi-spacecraft missions. We introduce the main results provided by them together with first observations of the turbulent cascade based on direct plasma measurements by the Spektr-R spacecraft in the magnetosheath. Recent results on solar wind effects on turbulence in the magnetosheath are also discussed.

scholarly journals Jump conditions for pressure anisotropy and comparison with the Earth's bow shock

2001 ◽  
Vol 8 (3) ◽  
pp. 167-174 ◽  
Author(s):  
D. F. Vogl ◽  
H. K. Biernat ◽  
N. V. Erkaev ◽  
C. J. Farrugia ◽  
S. Mühlbachler
Keyword(s):  
Magnetic Field ◽  
Tangential Component ◽  
Bow Shock ◽  
Jump Conditions ◽  
Plasma Parameters ◽  
Pressure Anisotropy ◽  
Threshold Conditions ◽  
Wind Spacecraft ◽  
Earth’S Bow Shock ◽  
The Magnetic Field

Abstract. Taking into account the pressure anisotropy in the solar wind, we study the magnetic field and plasma parameters downstream of a fast shock, as functions of upstream parameters and downstream pressure anisotropy. In our theoretical approach, we model two cases: a) the perpendicular shock and b) the oblique shock. We use two threshold conditions of plasma instabilities as additional equations to bound the range of pressure anisotropy. The criterion of the mirror instability is used for pressure anisotropy p \\perp /p\\parrallel > 1. Analogously, the criterion of the fire-hose instability is taken into account for pressure anisotropy p \\perp /p\\parrallel < 1. We found that the variations of the parallel pressure, the parallel temperature, and the tangential component of the velocity are most sensitive to the pressure anisotropy downstream of the shock. Finally, we compare our theory with plasma and magnetic field parameters measured by the WIND spacecraft.

The distribution function of diffuse ions and the magnetic field power spectrum upstream of Earth's bow shock

1987 ◽  
Vol 14 (7) ◽  
pp. 681-684 ◽  
Author(s):  
E. Möbius ◽  
M. Scholer ◽  
N. Sckopke ◽  
H. Lühr ◽  
G. Paschmann ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Distribution Function ◽  
Power Spectrum ◽  
Bow Shock ◽  
Earth’S Bow Shock ◽  
The Magnetic Field

scholarly journals Low-frequency magnetic variations at the high-<i>β</i> Earth bow shock

2019 ◽  
Vol 37 (5) ◽  
pp. 877-889
Author(s):  
Anatoli A. Petrukovich ◽  
Olga M. Chugunova ◽  
Pavel I. Shustov
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Spatial Scales ◽  
Low Frequency ◽  
Background Field ◽  
Bow Shock ◽  
Stable Phase ◽  
Main Magnetic Field ◽  
Astrophysical Plasmas ◽  
Earth’S Bow Shock

Abstract. Observations of Earth's bow shock during high-β (ratio of thermal to magnetic pressure) solar wind streams are rare. However, such shocks are ubiquitous in astrophysical plasmas. Typical solar wind parameters related to high β (here β>10) are as follows: low speed, high density, and a very low interplanetary magnetic field of 1–2 nT. These conditions are usually quite transient and need to be verified immediately upstream of the observed shock crossings. In this report, three characteristic crossings by the Cluster project (from the 22 found) are studied using multipoint analysis, allowing us to determine spatial scales. The main magnetic field and density spatial scale of about a couple of hundred of kilometers generally corresponds to the increased proton convective gyroradius. Observed magnetic variations are different from those for supercritical shocks, with β∼1. Dominant magnetic variations in the shock transition have amplitudes much larger than the background field and have a frequency of ∼ 0.3–0.5 Hz (in some events – 1–2 Hz). The wave polarization has no stable phase and is closer to linear, which complicates the determination of the wave propagation direction. Spatial scales (wavelengths) of variations are within several tens to a couple of hundred of kilometers.

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