Variation of quiet Sun magnetic elements between 2006 and 2011 using Hinode SOT/SP
Abstract
The Hinode satellite has revealed copious amounts of horizontal flux covering the quiet Sun, nurturing the notion of local dynamo action operating close to the solar surface. We sought to investigate the variation in the occurrence as well as the strength of circular and linear polarisation on the quiet Sun during the minimum of cycle 23, covering a period from November 2006 until August 2011. This investigation used Hinode SOT/SP images of the disk centre and a large FOV and focussed on line-integrated linear and circular polarisation signals obtained from the Fe I 6302.5 Å absorption line. The circular polarisation showed an overall linear decline in occurrence from November 2006 until August 2011. By comparing PDFs we found that this decline is associated in particular with network elements. The internetwork on the other hand showed a 10% decrease in occurrence from November 2010 until June 2009, followed by an equal increase until August 2011. The investigation also revealed a reduction of 30% in the occurrence of linear polarisation signals between November 2006 and December 2009. From August 2010 until August 2011 the occurrence of linear polarisation was increasing again. Hence, our results show that the occurrence of the ubiquitous linear polarisation of the internetwork as seen by Hinode is measurably influenced by the solar cycle. This implies that an independent local dynamo process is unlikely to be the sole cause responsible for the generation of this magnetic flux.
- Publication:
-
SDO-3: Solar Dynamics and Magnetism from the Interior to the Atmosphere
- Pub Date:
- October 2011
- Bibcode:
- 2011sdmi.confE..76B
- Keywords:
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- SDO;
- SDO-3;
- SDO 3;
- SDO Workshop;
- LWS/SDO-3/SOHO-26/GONG-2011 Workshop;
- Solar Dynamic Observatory