Topological Structures of Velocity and Electric Field in the Vicinity of a Cusp-type Magnetic Null Point

0511581 - ASÚ 2020 RIV US eng J - Journal Article
Nickeler, Dieter Horst - Karlický, Marian - Kraus, Michaela
Topological Structures of Velocity and Electric Field in the Vicinity of a Cusp-type Magnetic Null Point.
Astrophysical Journal. Roč. 873, č. 1 (2019), č. článku 41. ISSN 0004-637X. E-ISSN 1538-4357
R&D Projects: GA ČR(CZ) GA16-05011S
Institutional support: RVO:67985815
Keywords : magnetic reconnection * magnetohydrodynamics * analytical methods
OECD category: Astronomy (including astrophysics,space science)
Impact factor: 5.746, year: 2019
Method of publishing: Open access

Topological characteristics reveal important physical properties of plasma structures and astrophysical processes. Physical parameters and constraints are linked with topological invariants, which are important for describing magnetic reconnection scenarios. We analyze stationary nonideal Ohm's law concerning the Poincare classes of all involved physical fields in two dimensions by calculating the corresponding topological invariants of their Jacobian (here: particularly the eigenvalues) or Hessian matrices. The magnetic field is assumed to have a cusp structure, and the stagnation point of the plasma flow coincides with the cusp. We find that the stagnation point must be hyperbolic. Furthermore, the functions describing both the resistivity and the ohmic heating have a saddle-point structure, being displaced with respect to the cusp point. These results imply that there is no monotonous relation between current density and anomalous resistivity in the case of a two-dimensional standard magnetic cusp.
Permanent Link: http://hdl.handle.net/11104/0301817