Photospheric electric fields and energy fluxes in the eruptive active region NOAA 11158
- Space Sciences Laboratory, UC Berkeley, CA 94720 (United States)
- W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305 (United States)
How much electromagnetic energy crosses the photosphere in evolving solar active regions (ARs)? With the advent of high-cadence vector magnetic field observations, addressing this fundamental question has become tractable. In this paper, we apply the “PTD-Doppler-FLCT-Ideal” (PDFI) electric field inversion technique of Kazachenko et al. to a 6-day vector magnetogram and Doppler velocity sequence from the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory to find the electric field and Poynting flux evolution in NOAA 11158, which produced an X2.2 flare early on 2011 February 15. We find photospheric electric fields ranging up to 2 V cm{sup −1}. The Poynting fluxes range from [−0.6 to 2.3] × 10{sup 10} erg cm{sup −2} s{sup −1}, mostly positive, with the largest contribution to the energy budget in the range of [10{sup 9}−10{sup 10}] erg cm{sup −2} s{sup −1}. Integrating the instantaneous energy flux over space and time, we find that the total magnetic energy accumulated above the photosphere from the initial emergence to the moment before the X2.2 flare to be E=10.6×10{sup 32} erg, which is partitioned as 2.0×10{sup 32}erg and 8.6×10{sup 32} erg, respectively, between free and potential energies. Those estimates are consistent with estimates from preflare nonlinear force-free field extrapolations and the Minimum Current Corona estimates, in spite of our very different approach. This study of photospheric electric fields demonstrates the potential of the PDFI approach for estimating Poynting fluxes and opens the door to more quantitative studies of the solar photosphere and more realistic data-driven simulations of coronal magnetic field evolution.
- OSTI ID:
- 22882639
- Journal Information:
- Astrophysical Journal, Vol. 811, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Since 2009, the country of publication for this journal is the UK.; ISSN 0004-637X
- Country of Publication:
- United Kingdom
- Language:
- English
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