Potential structure near a probe in a flowing magnetoplasma and current collection

Singh, Nagendra; Leung, W.C.; Vashi, B.I.

doi:10.1029/96ja02917

Cited by 12 publications

(17 citation statements)

References 15 publications

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“…If the body size across the magnetic field line is D and the its perpendicular velocity is V o , it generates waves along the field lines at frequencies f ∼ V o / D , the inverse of the transit time of the plasma convecting past the body in its rest frame. This was demonstrated in experiments at UCLA for the transit time in the whistler regime [ Stenzel and Urrutia , 1989] also in electrostatic simulations for the NASA tethered satellite experiment of [ Singh et al , 1997]. The wave pattern in the experiment and the simulations were determined by group velocity angles.…”

Section: Conclusion and Discussionmentioning

confidence: 86%

Group velocity cones in diverging magnetic reconnection structures

Singh

2007

J. Geophys. Res.

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[1] In a typical geometry of magnetic reconnection, the so-called exhaust regions diverge out of the localized diffusion region. The diverging reconnection structure is conical in shape with its apex near the x-line. Such conical regions have been seen in both MHD and kinetic simulations of reconnection as well as in satellite observations. We demonstrate here that depending on the reconnection regime, the cone angle of the exhaust regions found in numerical simulations and as well as in satellite observations compare well with the maximum angles of group-velocity cones associated with the slow MHD mode, or the whistler mode, or the kinetic Alfvén wave (KAW). For each of these three reconnection regimes, we give a quantitative description of the group velocity cones. In the MHD case the cone angle is small and increases almost linearly with the plasma b < 2. In the whistler regime the cone angle is a constant of 19.5°. In the KAW regime the cone angle depends on plasma b as well as on the timescale associated with the diffusion process in the current sheet. The close agreement between the observed and simulated exhaust cone angles and the group-velocity cone angles in all the three reconnection regimes is highly suggestive that ''at least'' the geometrical feature of the exhaust region is determined by the group velocity of the disturbances, which propagate out of the diffusion region.

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Section: Conclusion and Discussionmentioning

confidence: 86%

Group velocity cones in diverging magnetic reconnection structures

Singh

2007

J. Geophys. Res.

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“…In three dimensional electrostatic particle-in-cell (PIC) simulations, Singh et al simulated positive probes (r p < r i ) in MDP and made observations of anomalous current collection, wing-like potential structures, and lower hybrid waves in the ion ram region that they identified as a free energy source for electron heating. [12][13][14] For negative probes in strongly magnetized underdense MDP, Hutchinson and Patacchini conducted a range of hybrid electrostatic PIC simulations, with emphasis on Mach probes in tokamaks and wake effects in dusty plasmas. 1,15 Since the probes were ion collecting, the electrons were well approximated using a Boltzmann fluid; a simplification that cannot be extended to positive probes where electron kinetics is important.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of positive probes in underdense, strongly magnetized, E×B drifting plasma: Particle-in-cell simulations

Heinrich

Cooke

2013

Physics of Plasmas

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Electron trapping, electron heating, space-charge wings, wake eddies, and current collection by a positive probe in E Â B drifting plasma were studied in three-dimensional electromagnetic particle-in-cell simulations. In these simulations, electrons and ions were magnetized with respect to the probe and the plasma was underdense (x pe < x ce ). A large drift velocity (Mach 4.5 with respect to the ion acoustic speed) between the plasma and probe was created with background electric and magnetic fields. Four distinct regions developed in the presences of the positive probe: a quasi-trapped electron region, an electron-depletion wing, an ion-rich wing, and a wake region. We report on the observations of strong electron heating mechanisms, space-charge wings, ion cyclotron charge-density eddies in the wake, electron acceleration due to a magnetic presheath, and the current-voltage relationship. [http://dx.

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“…Fig.2(a) shows the satellite charging process when satellite motion is parallel to magnetic field. In order to reduce the simulation time, the relative velocity (U d = 0.1(kT e /m e ) 1/2 ) is chosen to be a little larger [4] . The equilibrium potential is −2.10kT e /e, and a bit larger than the equilibrium potential (−2.51kT e /e) when U d = 0.…”

Section: Simulation Resultsmentioning

confidence: 99%

“…In the previous computer simulations, the convective electric field is ignored in the frame of satellite. But recent studies show that it plays a considerable role in the charging process in the existence of large magnetic field [4] .…”

Section: Introductionmentioning

confidence: 99%

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Plasma Sheath of Satellites Moving in Magnetized Plasma of Low Earth Orbit

Cao¹,

Wang²,

Zhou³

et al. 2000

Chinese J of Geophysics

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The charging process and plasma sheath structure of satellite moving in the magnetized plasma of low earth orbit are studied by means of 2 1/2‐D electrostatic code. The relative motion is simulated by plasma flowing past the satellite and therefore a convection electric field is imposed. The results show that, in the LEO orbit, the satellite is quickly (at time , ωpe is electron cyclotron frequency) charged up to the equilibrium negative potential. The increase of magnetic field makes absolute value of the negative potential decrease. The plasma sheath is symmetric around the satellite and is about several Debye lengths if the relative motion is not considered. The motion of the plasma will make the plasma sheath extend in the wake region.

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Potential structure near a probe in a flowing magnetoplasma and current collection

Cited by 12 publications

References 15 publications

Group velocity cones in diverging magnetic reconnection structures

Group velocity cones in diverging magnetic reconnection structures

Dynamics of positive probes in underdense, strongly magnetized, E×B drifting plasma: Particle-in-cell simulations

Plasma Sheath of Satellites Moving in Magnetized Plasma of Low Earth Orbit

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