Kinetic-scale flux rope reconnection in periodic and line-tied geometries

Journal Article · Thu Dec 28 00:00:00 EST 2017 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.5007860· OSTI ID:1417172

Sauppe, J. P.  ^[1]; Daughton, W. ^[1]

---

1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Here, the collisionless reconnection of two parallel flux ropes driven by both the coalescence and kink instabilities is examined using fully kinetic simulations in periodic and line-tied geometries. The three-dimensional reconnection rate is computed from the maximum of the quasi-potential, Ξ≡-∫E·dℓ, where the integral of the electric field is taken along the magnetic field lines across the system. In periodic simulations in which the kink mode is nearly suppressed, reconnection is driven by the coalescence instability, and the peak rate is within 3%–8% of comparable 2D simulations. When a strong kink growth is observed, the peak reconnection rate drops by 10%–25%, and there is a larger drop for lower guide field. With line-tied boundary conditions, the kink instability plays a key role in allowing the flux ropes to interact and partially reconnect. In this limit, the field lines with maximum quasi-potential are associated with a quasi-separatrix layer, and the electric field along these special field lines is supported predominantly by the divergence of the electron pressure tensor. Both of these features, along with the observed reconnection rate, are consistent with recent laboratory experiments on kinetic-scale flux ropes. In kinetic simulations, the non-gyrotropic pressure tensor terms contribute significantly more to the reconnecting electric field than do the gyrotropic terms, while contributions from the electron inertia are significant for field lines adjacent to the quasi-separatrix layer.

• Research Organization: Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Fusion Energy Sciences (FES)
• Grant/Contract Number: AC52-06NA25396
• OSTI ID: 1417172
• Alternate ID(s): OSTI ID: 1415058
• Report Number(s): LA-UR-17-28531; TRN: US1801002
• Journal Information: Physics of Plasmas, Vol. 25, Issue 1; ISSN 1070-664X
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
Heliospheric and Magnetospheric Physics