![]() Our results provide direct evidence for currents heating the lower solar chromosphere through Ohmic dissipation. The corresponding increase in internal energy of 200 J m −3 can be supplied by the heating in about 10 min.Ĭonclusions. 2019 Stories from The Bridge in 2020 Stories from The Bridge in 2021. The temperature enhancements and the Cowling heating are primarily confined to a height range of 0.4−0.7 Mm above the light bridge. The Bridge is a mix of wonderful stories about you, our alumni and the impact the. Only the light bridge, where relatively weak and highly inclined magnetic fields emerge over a duration of 13 h, shows a spatial coincidence of thermal enhancements and electric currents. These currents produce a chromospheric temperature excess of about 600−800 K relative to the umbra. We find that the light bridge is a site of strong electric currents, of about 0.3 A m −2 at the bottom boundary, which extend to about 0.7 Mm while decreasing monotonically with height. The photospheric magnetic field from HMI was extrapolated to the corona using a non-force-free field technique that provided the three-dimensional distribution of electric currents, while an inversion of the chromospheric Ca II line with a local thermodynamic equilibrium and a nonlocal thermodynamic equilibrium spectral archive delivered the temperature stratifications from the photosphere to the chromosphere. We combine high-resolution spectroscopic Ca II data from the Dunn Solar Telescope and vector magnetic field observations from the Helioseismic and Magnetic Imager (HMI) to investigate thermal enhancements in a sunspot light bridge. We aim to determine how Ohmic dissipation by electric currents can heat the solar chromosphere. ![]() Resistive Ohmic dissipation has been suggested as a mechanism for heating the solar chromosphere, but few studies have established this association.Īims. ![]() National Solar Observatory (NSO), 3665 Discovery Drive, Boulder, CO 80303, USAĭepartment of Physics and Astronomy, California State University, Northridge (CSUN), Northridge, CA 91330-8268, USAĬontext. Udaipur Solar Observatory, Physical Research Laboratory, Dewali Badi Road, Udaipur, 313001 Rajasthan, IndiaĮ-mail: for Space Plasma and Aeronomic Research, The University of Alabama in Huntsville, Huntsville, AL 35899, USA Louis 1, Avijeet Prasad 2, Christian Beck 3, Debi P.
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