Abstract
We investigate the sizes of 86 non-flaring solar active regions with
respect to the brightness temperature at 8 mm and active region magnetic
field strength. The data were collected in AprilŰSeptember, 2014,
and AprilŰJuly, 2015 at Aalto University, Metsähovi Radio
Observatory with the 14-m radio telescope. The observations were made at
the maximum of the solar cycle 24. We used active region magnetic field
strength values measured with the Helioseismic and Magnetic Imager
instrument aboard the Solar Dynamics Observatory. We calculated that the
mean active region size in percentage of the full solar disk is 3.7
ś 0.86%. In addition, the mean temperature of selected active
regions is around 109% of the quiet Sun level and the average magnetic
field strength of the studied active region is 1,400 G. Our results show
correlation between active region sizes, the total brightness
temperature of the Sun, and the active region magnetic field strengths.
Original language | English |
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Pages (from-to) | 398-406 |
Number of pages | 9 |
Journal | Astronomische Nachrichten |
Volume | 338 |
Issue number | 4 |
DOIs | |
Publication status | Published - 1 May 2017 |
MoE publication type | A1 Journal article-refereed |
Keywords
- Magnetic field
- Radio brightening
- Sun: Solar activity
- Sunspot
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Metsähovi Radio Observatory
Tammi, J. (Manager)
School of Electrical EngineeringFacility/equipment: Facility