Two-dimensional MHD model of the reconnection diffusion region

Еркаев, Н. В.; Семенов, В. С.; Biernat, H. K.

doi:10.5194/npg-9-131-2002

Cited by 7 publications

(8 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Next, following standard procedure, 6,29 we expand the inflow quantities in powers of the inflow Alfv en Mach number, M A ¼ u(0, a 0 ) ¼ E(0, a 0 ). The perpendicular field and flow components b and u are of first order in M A , while the parallel field and flow components V and B are of zeroth order.…”

Section: Averaged Resistive Mhd Equationsmentioning

confidence: 99%

“…We also assume that variations in x are of order unity (i.e., @/@x %1/L), while variations in y are of order 1/M A (i.e., @/@y %1/a 0 ). These approximations reduce (3), (6), and (7) to…”

Section: Averaged Resistive Mhd Equationsmentioning

confidence: 99%

“…For example, it occurs when the electrical resistivity in the vicinity of the X-line is locally enhanced. [2][3][4][5][6] More recently, Baty et al 7,8 have found that Petschek reconnection can also be generated using a nonuniform viscosity profile 8 or imposing an asymmetric, nonuniform resistivity in the form of a simple step function. 7 The possible conditions that can produce Petschek reconnection are, therefore, more varied than is commonly realized.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Indeterminacy and instability in Petschek reconnection

et al. 2013

View full text Add to dashboard Cite

We explain two puzzling aspects of Petschek's model for fast reconnection. One is its failure to occur in plasma simulations with uniform resistivity. The other is its inability to provide anything more than an upper limit for the reconnection rate. We have found that previously published analytical solutions based on Petschek's model are structurally unstable if the electrical resistivity is uniform. The structural instability is associated with the presence of an essential singularity at the X-line that is unphysical. By requiring that such a singularity does not exist, we obtain a formula that predicts a specific rate of reconnection. For uniform resistivity, reconnection can only occur at the slow, Sweet-Parker rate. For nonuniform resistivity, reconnection can occur at a much faster rate provided that the resistivity profile is not too flat near the X-line. If this condition is satisfied, then the scale length of the nonuniformity determines the reconnection rate.

show abstract

Section: Averaged Resistive Mhd Equationsmentioning

confidence: 99%

“…We also assume that variations in x are of order unity (i.e., @/@x %1/L), while variations in y are of order 1/M A (i.e., @/@y %1/a 0 ). These approximations reduce (3), (6), and (7) to…”

Section: Averaged Resistive Mhd Equationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Indeterminacy and instability in Petschek reconnection

et al. 2013

View full text Add to dashboard Cite

show abstract

“…For H + e , exactly the opposite is true, with northward flows at positive y-locations and southward flows at negative y-locations. As already noted, magnetic reconnection occurs between the magnetic field of the cloud and the IMF (Erkaev et al, 2002;Dasso et al, 2007). For H − e , magnetic reconnection takes place on the back side flank at negative y-coordinates, and for H + e , magnetic reconnection takes place on the front side flank at positive y-coordinates, where orientations of IMF lines and MC field lines become antiparallel.…”

Section: Evolution Of the MC Cross Section In The Equatorial Planementioning

confidence: 94%

The role of magnetic handedness in magnetic cloud propagation

et al. 2010

Self Cite

View full text Add to dashboard Cite

Abstract.We investigate the propagation of magnetic clouds (MCs) through the inner heliosphere using 2.5-D ideal magnetohydrodynamic (MHD) simulations. A numerical solution is obtained on a spherical grid, either in a meridional plane or in an equatorial plane, by using a Roe-type approximate Riemann solver in the frame of a finite volume approach. The structured background solar wind is simulated for a solar activity minimum phase. In the frame of MC propagation, special emphasis is placed on the role of the initial magnetic handedness of the MC's force-free magnetic field because this parameter strongly influences the efficiency of magnetic reconnection between the MC's magnetic field and the interplanetary magnetic field. Magnetic clouds with an axis oriented perpendicular to the equatorial plane develop into an elliptic shape, and the ellipse drifts into azimuthal direction. A new feature seen in our simulations is an additional tilt of the ellipse with respect to the direction of propagation as a direct consequence of magnetic reconnection. During propagation in a meridional plane, the initial circular cross section develops a concave-outward shape. Depending on the initial handedness, the cloud's magnetic field may reconnect along its backside flanks to the ambient interplanetary magnetic field (IMF), thereby losing magnetic flux to the IMF. Such a process in combination with a structured ambient solar wind has never been analyzed in detail before. Furthermore, we address the topics of force-free magnetic field conservation and the development of equatorward flows ahead of a concave-outward shaped MC. Detailed profiles are presented for the radial evolution of magnetoplasma and geometrical parameters. The principal features seen in our MHD simulations are in good agreement with in-situ meaCorrespondence to: U. Taubenschuss (ulrich.taubenschuss@oeaw.ac.at) surements performed by spacecraft. The 2.5-D studies presented here may serve as a basis under more simple geometrical conditions to understand more complicated effects seen in 3-D simulations.

show abstract

“…It was shown later that spatial non-uniform resistivity is required to support the Petschek type scenario (e.g. Sato and Hayashi, 1979;Biskamp, 1986;Erkaev et al, 2000;Biskamp and Schwarz, 2001;Erkaev et al, 2002). This anomalous resistivity in collisionless plasmas may be caused by microinstabilities, such as the lower hybrid drift instability (Huba et al, 1977), the Buneman instability (Drake et al, 2003), the ion-acoustic instability (Kan, 1971;Coroniti, 1985), or others (Büchner and Daughton, 2007).…”

Section: Fast Reconnectionmentioning

confidence: 99%

Collisionless magnetic reconnection: analytical model and PIC simulation comparison

et al. 2009

View full text Add to dashboard Cite

Abstract. Magnetic reconnection is believed to be responsible for various explosive processes in the space plasma including magnetospheric substorms. The Hall effect is proved to play a key role in the reconnection process. An analytical model of steady-state magnetic reconnection in a collisionless incompressible plasma is developed using the electron Hall MHD approximation. It is shown that the initial complicated system of equations may split into a system of independent equations, and the solution of the problem is based on the Grad-Shafranov equation for the magnetic potential. The results of the analytical study are further compared with a two-dimensional particle-in-cell simulation of reconnection. It is shown that both methods demonstrate a close agreement in the electron current and the magnetic and electric field structures obtained. The spatial scales of the acceleration region in the simulation and the analytical study are of the same order. Such features like particles trajectories and the in-plane electric field structure appear essentially similar in both models.

show abstract

Two-dimensional MHD model of the reconnection diffusion region

Cited by 7 publications

References 8 publications

Indeterminacy and instability in Petschek reconnection

Indeterminacy and instability in Petschek reconnection

The role of magnetic handedness in magnetic cloud propagation

Collisionless magnetic reconnection: analytical model and PIC simulation comparison

Contact Info

Product

Resources

About