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HMI observations of two types of ephemeral regions

Published online by Cambridge University Press:  06 January 2014

Shuhong Yang ,
Jun Zhang  and
Yang Liu
Shuhong Yang
Affiliation:
Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China email: shuhongyang@nao.cas.cn
Jun Zhang
Affiliation:
Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China email: shuhongyang@nao.cas.cn
Yang Liu
Affiliation:
W.W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305-4085, USA
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Abstract

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Using the magnetograms observed with the Helioseismic and Magnetic Imager, we statistically study the ephemeral regions (ERs) of the Sun. we notice that the areas with locations around S15° and N25° have larger ER number density, implying that the generation of ERs may be affected by the large-scale background fields from dispersed active regions. According to their evolution, the ERs can be classified into two types, i.e., normal ERs (2798 ones) and self-canceled ERs (190 ones). Submergence of initial magnetic flux loops connecting the opposite dipolar polarities may lead to the self-cancellation.

Keywords

Sun: evolutionSun: photosphereSun: surface magnetism
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 8 , Symposium S300: Nature of Prominences and their role in Space Weather , June 2013 , pp. 470 - 472
Copyright
Copyright © International Astronomical Union 2013 

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