Publication Date:
2014-10-18
Description:
The physical processes causing energy exchange between the Sun's hot corona and its cool lower atmosphere remain poorly understood. The chromosphere and transition region (TR) form an interface region between the surface and the corona that is highly sensitive to the coronal heating mechanism. High-resolution observations with the Interface Region Imaging Spectrograph (IRIS) reveal rapid variability (~20 to 60 seconds) of intensity and velocity on small spatial scales ( less, similar500 kilometers) at the footpoints of hot and dynamic coronal loops. The observations are consistent with numerical simulations of heating by beams of nonthermal electrons, which are generated in small impulsive ( less, similar30 seconds) heating events called "coronal nanoflares." The accelerated electrons deposit a sizable fraction of their energy ( less, similar10(25) erg) in the chromosphere and TR. Our analysis provides tight constraints on the properties of such electron beams and new diagnostics for their presence in the nonflaring corona.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Testa, P -- De Pontieu, B -- Allred, J -- Carlsson, M -- Reale, F -- Daw, A -- Hansteen, V -- Martinez-Sykora, J -- Liu, W -- DeLuca, E E -- Golub, L -- McKillop, S -- Reeves, K -- Saar, S -- Tian, H -- Lemen, J -- Title, A -- Boerner, P -- Hurlburt, N -- Tarbell, T D -- Wuelser, J P -- Kleint, L -- Kankelborg, C -- Jaeggli, S -- New York, N.Y. -- Science. 2014 Oct 17;346(6207):1255724. doi: 10.1126/science.1255724.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA. ptesta@cfa.harvard.edu. ; Lockheed Martin Solar and Astrophysics Laboratory, 3251 Hanover Street, Org. A021S, Building 252, Palo Alto, CA 94304, USA. Institute of Theoretical Astrophysics, University of Oslo, Post Office Box 1029, Blindern, N-0315, Oslo, Norway. ; NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA. ; Institute of Theoretical Astrophysics, University of Oslo, Post Office Box 1029, Blindern, N-0315, Oslo, Norway. ; Dipartimento di Fisica e Chimica, Universita' di Palermo and Istituto Nazionale di Astrofisica (INAF)/Osservatorio Astronomico di Palermo, Piazza del Parlamento 1, 90134 Palermo, Italy. ; Bay Area Environmental Research Institute 596 1st Street West, Sonoma, CA 95476, USA. ; Lockheed Martin Solar and Astrophysics Laboratory, 3251 Hanover Street, Org. A021S, Building 252, Palo Alto, CA 94304, USA. W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305, USA. ; Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA. ; Lockheed Martin Solar and Astrophysics Laboratory, 3251 Hanover Street, Org. A021S, Building 252, Palo Alto, CA 94304, USA. ; Lockheed Martin Solar and Astrophysics Laboratory, 3251 Hanover Street, Org. A021S, Building 252, Palo Alto, CA 94304, USA. Bay Area Environmental Research Institute 596 1st Street West, Sonoma, CA 95476, USA. ; Department of Physics, Montana State University, Bozeman, Post Office Box 173840, Bozeman, MT 59717, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25324396" target="_blank"〉PubMed〈/a〉
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
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Chemistry and Pharmacology
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Computer Science
,
Medicine
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Natural Sciences in General
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Physics
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