Correlation Between the Magnetic Field and Plasma Parameters at 1 AU

On 14 January 2008, the MESSENGER spacecraft, during its first flyby around Mercury, recorded the magnetic field structure, which was later called the “double magnetopause”. The role of sodium ions penetrating into the Hermean magnetosphere from the magnetosheath in generation of this structure has been discussed since then. The violation of the symmetry of the plasma parameters at the magnetopause is the cause of the magnetizing current generation. Here, we consider whether the change in the density of sodium ions on both sides of the Hermean magnetopause could be the cause of a wide diamagnetic current in the magnetosphere at its dawn-side boundary observed during the first MESSENGER flyby. In the present paper, we propose an analytical approach that made it possible to determine the magnetosheath Na+ density excess providing the best agreement between the calculation results and the observed magnetic field in the double magnetopause.

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Experimental and numerical investigation of plasma parameters in the magnetosheath

MATEC Web of Conferences ◽

10.1051/matecconf/201814503003 ◽

2018 ◽

Vol 145 ◽

pp. 03003

Author(s):

Polya Dobreva ◽

Monio Kartalev ◽

Olga Nitcheva ◽

Natalia Borodkova ◽

Georgy Zastenker

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Numerical Investigation ◽

Euler Equations ◽

Ideal Gas ◽

Bow Shock ◽

Plasma Parameters ◽

Wind Spacecraft ◽

The Magnetic Field ◽

Good Agreement

We investigate the behaviour of the plasma parameters in the magnetosheath in a case when Interball-1 satellite stayed in the magnetosheath, crossing the tail magnetopause. In our analysis we apply the numerical magnetosheath-magnetosphere model as a theoretical tool. The bow shock and the magnetopause are self-consistently determined in the process of the solution. The flow in the magnetosheath is governed by the Euler equations of compressible ideal gas. The magnetic field in the magnetosphere is calculated by a variant of the Tsyganenko model, modified to account for an asymmetric magnetopause. Also, the magnetopause currents in Tsyganenko model are replaced by numericaly calulated ones. Measurements from WIND spacecraft are used as a solar wind monitor. The results demonstrate a good agreement between the model-calculated and measured values of the parameters under investigation.

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A case study of the plasma in the magneto-sheath using the numerical magnetosheath-magnetosphere model and THEMIS measure-ments

MATEC Web of Conferences ◽

10.1051/matecconf/201814503004 ◽

2018 ◽

Vol 145 ◽

pp. 03004

Author(s):

Polya Dobreva ◽

Olga Nitcheva ◽

Monio Kartalev

Keyword(s):

Magnetic Field ◽

Field Model ◽

Specific Aspect ◽

Plasma Parameters ◽

Ion Density ◽

Magnetic Field Model ◽

Wind Spacecraft ◽

The Mean ◽

The Magnetic Field

This paper presents a case study of the plasma parameters in the magnetosheath, based on THEMIS measurements. As a theoretical tool we apply the self-consistent magnetosheath-magnetosphere model. A specific aspect of the model is that the positions of the bow shock and the magnetopause are self-consistently determined. In the magnetosheath the distribution of the velocity, density and temperature is calculated, based on the gas-dynamic theory. The magnetosphere module allows for the calculation of the magnetopause currents, confining the magnetic field into an arbitrary non-axisymmetric magnetopause. The variant of the Tsyganenko magnetic field model is applied as an internal magnetic field model. As solar wind monitor we use measurements from the WIND spacecraft. The results show that the model quite well reproduces the values of the ion density and velocity in the magnetosheath. The simlicity of the model allows calulations to be perforemed on a personal computer, which is one of the mean advantages of our model.

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Magnetic field effect on laser-induced breakdown spectroscopy and surface modifications of germanium at various fluences

Laser and Particle Beams ◽

10.1017/s0263034617000039 ◽

2017 ◽

Vol 35 (1) ◽

pp. 159-169 ◽

Cited By ~ 11

Author(s):

H. Iftikhar ◽

S. Bashir ◽

A. Dawood ◽

M. Akram ◽

A. Hayat ◽

...

Keyword(s):

Magnetic Field ◽

Electron Temperature ◽

Surface Modifications ◽

Laser Induced Breakdown Spectroscopy ◽

Excitation Temperature ◽

Number Density ◽

Plasma Parameters ◽

Breakdown Spectroscopy ◽

Laser Induced Breakdown ◽

The Magnetic Field

AbstractThe effect of the transverse magnetic field on laser-induced breakdown spectroscopy and surface modifications of germanium (Ge) has been investigated at various fluences. Ge targets were exposed to Nd: YAG laser pulses (1064 nm, 10 ns, 1 Hz) at different fluences ranging from 3 to 25.6 J/cm2 to generate Ge plasma under argon environment at a pressure of 50 Torr. The magnetic field of strength 0.45 Tesla perpendicular to the direction of plasma expansion was employed by using two permanent magnets. The emission spectra of laser-induced Ge plasma was detected by the laser-induced breakdown spectroscopy system. The electron temperature and number density of Ge plasma are evaluated by using the Boltzmann plot and stark broadening methods, respectively. The variations in emission intensity, electron temperature (Te), and number density (ne) of Germanium plasma are explored at various fluences, with and without employment of the magnetic field. It is observed that the magnetic field is responsible for significant enhancement of both excitation temperature and number density at all fluences. It is revealed that an excitation temperature increases from Te,max,without B = 16,190 to Te,max,with B = 20,123 K. Similarly, the two times enhancement in the electron density is observed from ne,max,without B = 2 × 1018 to ne,max,with B = 4 × 1018 cm−3. The overall enhancement in Ge plasma parameters in the presence of the magnetic field is attributed to the Joule heating effect and adiabatic compression. With increasing fluence both plasma parameters increase and achieve their maxima at a fluence of 12.8 J/cm2 and then decrease. In order to correlate the plasma parameters with surface modification, scanning electron microscope analysis of irradiated Ge was performed. Droplets and cones are formed for both cases. However, the growth of ridges and distinctness of features is more pronounced in case of the absence of the magnetic field; whereas surface structures become more diffusive in the presence of the magnetic field.

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

Nonlinear Processes in Geophysics ◽

10.5194/npg-8-167-2001 ◽

2001 ◽

Vol 8 (3) ◽

pp. 167-174 ◽

Cited By ~ 11

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.

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Cluster survey of the high-altitude cusp properties: a three-year statistical study

Annales Geophysicae ◽

10.5194/angeo-22-3009-2004 ◽

2004 ◽

Vol 22 (8) ◽

pp. 3009-3019 ◽

Cited By ~ 33

Author(s):

B. Lavraud ◽

A. Fedorov ◽

E. Budnik ◽

A. Grigoriev ◽

P. J. Cargill ◽

...

Keyword(s):

Magnetic Field ◽

High Altitude ◽

External Boundary ◽

Plasma Parameters ◽

Pressure Distributions ◽

Magnetic Field Model ◽

Statistical Sense ◽

Statistical Survey ◽

Low Magnetic Field ◽

The Magnetic Field

Abstract. The global characteristics of the high-altitude cusp and its surrounding regions are investigated using a three-year statistical survey based on data obtained by the Cluster spacecraft. The analysis involves an elaborate orbit-sampling methodology that uses a model field and takes into account the actual solar wind conditions and level of geomagnetic activity. The spatial distribution of the magnetic field and various plasma parameters in the vicinity of the low magnetic field exterior cusp are determined and it is found that: 1) The magnetic field distribution shows the presence of an intermediate region between the magnetosheath and the magnetosphere: the exterior cusp, 2) This region is characterized by the presence of dense plasma of magnetosheath origin; a comparison with the Tsyganenko (1996) magnetic field model shows that it is diamagnetic in nature, 3) The spatial distributions show that three distinct boundaries with the lobes, the dayside plasma sheet and the magnetosheath surround the exterior cusp, 4) The external boundary with the magnetosheath has a sharp bulk velocity gradient, as well as a density decrease and temperature increase as one goes from the magnetosheath to the exterior cusp, 5) While the two inner boundaries form a funnel, the external boundary shows no clear indentation, 6) The plasma and magnetic pressure distributions suggest that the exterior cusp is in equilibrium with its surroundings in a statistical sense, and 7) A preliminary analysis of the bulk flow distributions suggests that the exterior cusp is stagnant under northward IMF conditions but convective under southward IMF conditions.

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On the excitation of higher harmonic electrostatic dust cyclotron waves

Journal of Plasma Physics ◽

10.1017/s0022377813000330 ◽

2013 ◽

Vol 79 (5) ◽

pp. 721-726

Author(s):

M. ROSENBERG

Keyword(s):

Magnetic Field ◽

Magnetized Plasma ◽

Wave Number ◽

Charged Dust ◽

Plasma Parameters ◽

Coulomb Collisions ◽

Plasma Device ◽

Higher Harmonic ◽

Parameter Ranges ◽

The Magnetic Field

AbstractIn a magnetized plasma containing charged dust whose motion is magnetized, one of the fundamental collective modes that could occur is the electrostatic dust cyclotron (EDC) wave with frequency near the dust cyclotron frequency. The EDC wave propagates nearly perpendicular to the magnetic field with a small parallel wave number, so that it can be driven unstable by ion flow along the magnetic field. Because unstable parallel wavelengths can be relatively large, this places constraints on the plasma device size. In this paper, we use linear kinetic theory to investigate the excitation of higher harmonic EDC waves that have wavelengths smaller than that of the fundamental mode. Collisions of charged particles with neutrals and Coulomb collisions including dust–dust collisions are taken into account. Constraints on possible parameter ranges arising from collisional effects or from requiring stability of other waves are discussed. Numerical results are presented for possible sets of laboratory dusty plasma parameters.

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Relativistic cross-focusing of extraordinary and ordinary modes in a magnetoactive plasma

Journal of Plasma Physics ◽

10.1017/s002237781300086x ◽

2013 ◽

Vol 79 (5) ◽

pp. 953-961 ◽

Cited By ~ 4

Author(s):

MEENU ASTHANA VARSHNEY ◽

SHALINI SHUKLA ◽

SONU SEN ◽

DINESH VARSHNEY

Keyword(s):

Magnetic Field ◽

Laser Beam ◽

Magnetoactive Plasma ◽

Plasma Parameters ◽

Self Focusing ◽

Second Mode ◽

Polarized Beam ◽

Set Up ◽

Overdense Plasma ◽

The Magnetic Field

AbstractThis paper presents the effect of self-focusing on a circularly polarized beam propagating along the static magnetic field when the extraordinary and ordinary modes are present simultaneously for relativistic intensities. The nonlinearity in the dielectric function arises on account of the relativistic variation of mass, which leads to the mutual coupling of the two modes that support the self-focusing of each other. The propagation and focusing of the first mode affects the propagation and focusing of the second mode. The fact that the two modes are laser-intensity dependent leads to cross-focusing. Dynamics of one laser beam affects the dynamics of the second laser beam. When both the beams or modes are strong, the nonlinearities introduced by the relativistic effect in the presence of the magnetic field are additive in nature, such that one beam can undergo oscillatory self-focusing and other beam simultaneously defocusing and vice versa. The dynamical equation governing the cross-focusing has been set up and a numerical solution has been presented for typical relativistic laser–plasma parameters from a slightly underdense to overdense plasma.

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Cluster observations of reconnection due to the Kelvin-Helmholtz instability at the dawnside magnetospheric flank

Annales Geophysicae ◽

10.5194/angeo-24-2619-2006 ◽

2006 ◽

Vol 24 (10) ◽

pp. 2619-2643 ◽

Cited By ~ 106

Author(s):

K. Nykyri ◽

A. Otto ◽

B. Lavraud ◽

C. Mouikis ◽

L. M. Kistler ◽

...

Keyword(s):

Magnetic Field ◽

Wave Vector ◽

Wave Length ◽

Normal Component ◽

Helmholtz Instability ◽

Plasma Parameters ◽

Parker Spiral ◽

Mhd Simulations ◽

The Magnetic Field ◽

The Imf

Abstract. On 3 July 2001, the four Cluster satellites traversed along the dawnside magnetospheric flank and observed large variations in all plasma parameters. The estimated magnetopause boundary normals were oscillating in the z-direction and the normal component of the magnetic field showed systematic 2–3 min bipolar variations for 1 h when the IMF had a small positive bz-component and a Parker-spiral orientation in the x,y-plane. Brief 33 s intervals with excellent deHoffman Teller frames were observed satisfying the Walén relation. Detailed comparisons with 2-D MHD simulations indicate that Cluster encountered rotational discontinuities generated by Kelvin-Helmholtz instability. We estimate a wave length of 6 RE and a wave vector with a significant z-component.

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Generation of terahertz radiation by beating of two laser beams in collisional magnetized plasma

Laser and Particle Beams ◽

10.1017/s0263034616000513 ◽

2016 ◽

Vol 34 (4) ◽

pp. 569-575 ◽

Cited By ~ 5

Author(s):

A. Hematizadeh ◽

S.M. Jazayeri ◽

B. Ghafary

Keyword(s):

Magnetic Field ◽

Magnetized Plasma ◽

Laser Beams ◽

Thz Radiation ◽

Plasma Parameters ◽

Circularly Polarized ◽

Left Hand ◽

Polarized Waves ◽

Radiation Generation ◽

The Magnetic Field

AbstractThis paper presents analytical calculations for terahertz (THz) radiation by beating of two cosh-Gaussian laser beams in a density rippled collisional magnetized plasma. Lasers beams exert a ponderomotive force on the electrons of plasma in beating frequency which generates THz waves. The magnetic field was considered parallel to the direction of lasers which leads to propagate right-hand circularly polarized or left-hand circularly polarized waves in the plasma depending on the phase matching conditions. Effects of collision frequency, decentered parameter of lasers and the magnetic field strength are analyzed for THz radiation generation. By the optimization of laser and plasma parameters, the efficiency of order 27% can be achieved.

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