Extending the concept of separatrices to QSLs for magnetic reconnection
Abstract
Magnetic reconnection is usually thought to be linked to the presence of magnetic null points and to be accompanied by the transport of magnetic field lines across separatrices, the set of field lines where the mapping of field lines is discontinuous. However, this view is too restrictive taking into account the variety of observed solar flaring configurations. Indeed ``quasi-separatrix layers" (QSLs), which are regions where there is drastic change in field-line linkage generalize the definition of separatrices. The use of this broader concept allows us to localize these thin regions where magnetic reconnection can preferentially occur in three-dimensional magnetic configurations. I will survey the evolution of the QSL concept from the beginning to the recent developments. The application to solar observations requires first the computation of the coronal magnetic field from photospheric data. Then, the determination of the QSLs allows us to understand the observed location of flare kernels and loops and so to validate the reconnection scenario as the main physical process at the origin of flares. On the theoretical side, locating the QSLs let us predict where strong current layers will form as a consequence of boundary evolution. Numerical simulations broadly confirm this, with direct implications for coronal heating. This QSL approach is also compatible with an MHD turbulence scenario for coronal heating as numerical simulations show the development of MHD turbulence when reconnection starts in QSLs.
- Publication:
-
35th COSPAR Scientific Assembly
- Pub Date:
- 2004
- Bibcode:
- 2004cosp...35.1084D