Microwave emission from steady and moving sunspots

Title:

Microwave emission from steady and moving sunspots

Creator:

Allissandrakis, C. E., Chiuderi Drago, F., and Hagyard, M. J.

Identifier:

https://cdk.lib.cas.cz/client/handle/uuid:5ce3a0b1-7e05-411a-974c-37e3def0fde9
uuid:5ce3a0b1-7e05-411a-974c-37e3def0fde9

Subject:

astrophysics, photospheric magnetic field, and sunspots

Type:

model:article and TEXT

Format:

bez média and svazek

Description:

We have used force-free extrapolations of photospheric magnetic field observations from Marshall Space Fllght Center to compute the total intensity and circular polarisation of sunspot associated emission from active region 2502 in the period June 13 to 15, 1980. The computed maps were compared to high resolution observations of tne same active region obtained witn tne Westerbork Synthesis Radio Telescope, Tne most interesting aspect of tne active region was tne developement of a new spot between the proceeding and the following spots on June 14, wnich subsequently merged witn the preceeding spot. The new spot was associated witn enhanced microwave emission with a peak brigtness temperature in excess of 4 10^6 K. Our model computations are In satisfactory agreement witn tne sunspot observations for June 13, nowever tbey falled to reproduce tne enhanced emission associated witn tne new spot on June 14 and 15. We snow tnat unrealistic values of tne conductive flux are required for the interpretation of tne emission of the new sunspot in terms of thermal processes. We suggest tnat tnis source Is due to gyrosynchrotron radiation from mildly relativistic electrons accelerated by reslstive instabiltles in tne evolvlng magnetic field.

Language:

Czech

Rights:

http://creativecommons.org/publicdomain/mark/1.0/
policy:public

Coverage:

267-270

Source:

Publications of the Astronomical Institute of the Academy of Sciences of the Czech Republic | 1987 Volume:63-70 | Number:66

Harvested from:

CDK

Metadata only:

false