Effects of Cowling Resistivity in the Weakly-Ionized Chromosphere

Abstract

The physics of the solar chromosphere is complex from both theoretical and modeling perspectives. The plasma temperature from the photosphere to corona increases from ~5,000 K to ~1 million K over a distance of only ~10,000 km from the chromosphere and the transition region. Certain regions of the solar atmosphere have sufficiently low temperature and ionization rates to be considered as weakly-ionized. In particular, this is true at the lower chromosphere. As a result, the Cowling resistivity is orders of magnitude greater than the Coulomb resistivity. Ohm's law therefore includes anisotropic dissipation. To evaluate the Cowling resistivity, we need to know the external magnetic field strength and to estimate the neutral fraction as a function of the bulk plasma density and temperature. In this study, we determine the magnetic field topology using the non-force-free field (NFFF) extrapolation technique based on SDO/HMI SHARP vector magnetogram data, and the stratified density and temperature profiles from the Maltby-M umbral core model for sunspots. We investigate the variation and effects of Cowling resistivity on heating and magnetic reconnection in the chromosphere as the flare-producing active region (AR) 11166 evolves. In particular, we analyze a C2.0 flare emerging from AR11166 and find a normalized reconnection rate of 0.051.

arXiv comment15 pages, 5 figures, The Astrophysical Journal Letters (in press)

References in corpus (10)

• The Interface Region Imaging Spectrograph (IRIS)
• Structure, Stability, and Evolution of Magnetic Flux Ropes from the Perspective of Magnetic Twist
• Multi-fluid simulations of chromospheric magnetic reconnection in a weakly ionized reacting plasma
• How did a Major Confined Flare Occur in Super Solar Active Region 12192?
• Reconnection in the ISM
• Successive flux rope eruptions from $\delta$-Sunspots region of NOAA 12673 and associated X-class eruptive flares on 2017 September 6
• Ion-neutral interactions and non-equilibrium ionization in the solar chromosphere
• A Practical Approach to Coronal Magnetic Field Extrapolation Based on the Principle of Minimum Dissipation Rate
• Magnetohydrodynamic simulation of magnetic null-point reconnections in NOAA AR12192 initiated with an extrapolated non-force-free-field
• On the effects of ion-neutral interactions in solar plasmas

Cited by in corpus (6)

• Magnetohydrodynamic Simulation of Magnetic Null-point Reconnections and Coronal dimmings during the X2.1 flare in NOAA AR 11283
• Two-fluid Modeling of Acoustic Wave Propagation in Gravitationally Stratified Isothermal Media
• Could switchbacks originate in the lower solar atmosphere? I. Formation mechanisms of switchbacks
• Heating of the solar chromosphere in a sunspot light bridge by electric currents
• The magnetic topology of the inverse Evershed flow
• Sustained heating of the chromosphere and transition region over a sunspot light bridge