Naslov
Quasi-equilibrium current sheet and the onset of impulsive bursty reconnection

Autori
Skender, Marina ; Lapenta, Giovanni

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, pp prezentacija, znanstveni

Skup
12th Quadrennial Solar-Terrestrial Physics Symposium

Mjesto i datum
Berlin, Njemačka, 12.07.2010. - 16.07.2010

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
quasiequlibrium current sheet, impulsive bursty reconnection, tearing-mode instability, aspect ratio

Sažetak
A two-dimensional reconnecting current sheet is studied numerically in the magnetohydrodynamic approach. Different simulation setups are employed in order to follow the evolution of the formed current sheet in diverse configurations: two types of initial equilibria, Harris and force-free, two types of boundary conditions, periodic and open, with uniform and nonuniform grid set, respectively. All the simulated cases are found to exhibit qualitatively the same behavior in which a current sheet evolves slowly through a series of quasiequilibria ; eventually it fragments and enters a phase of fast impulsive bursty reconnection. In order to gain more insight on the nature and characteristics of the instability taking place, physical characteristics of the simulated current sheet are related to its geometrical properties. At the adopted Lundquist number of S =104 and Reynolds number R =104, the ratio of the length to width (aspect ratio) of the formed current sheet is observed to increase slowly in time up to a maximum value at which it fragments. Moreover, additional turbulence applied to the system is shown to exhibit the same qualitative steps, but with the sooner onset of the fragmentation and at smaller aspect ratio.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

POVEZANOST RADA