Bihelical Spectrum of Solar Magnetic Helicity and Its Evolution

被引：17

作者：

Singh, Nishant K. ^{[1
]}

Kaepylae, Maarit J. ^{[1
,2
]}

Brandenburg, Axel ^{[3
,4
,5
,6
,7
,8
]}

Kaepylae, Petri J. ^{[1
,2
,9
]}

Lagg, Andreas ^{[1
]}

Virtanen, Ilpo ^{[10
]}

机构：

[1] Max Planck Inst Solar Syst Res, Justus von Liebig Weg 3, D-37077 Gottingen, Germany

[2] Aalto Univ, ReSoLVE Ctr Excellence, Dept Comp Sci, POB 15400, FI-00076 Aalto, Finland

[3] KTH Royal Inst Technol, NORDITA, Roslagstullsbacken 23, SE-10691 Stockholm, Sweden

[4] Stockholm Univ, Roslagstullsbacken 23, SE-10691 Stockholm, Sweden

[5] Stockholm Univ, AlbaNova Univ Ctr, Dept Astron, SE-10691 Stockholm, Sweden

[6] Univ Colorado, JILA, Box 440, Boulder, CO 80303 USA

[7] Univ Colorado, Dept Astrophys & Planetary Sci, Box 440, Boulder, CO 80303 USA

[8] Lab Atmospher & Space Phys, 3665 Discovery Dr, Boulder, CO 80303 USA

[9] Leibniz Inst Astrophys Potsdam, Sternwarte 16, D-14482 Potsdam, Germany

[10] Univ Oulu, Space Climate Res Unit, ReSoLVE Ctr Excellence, POB 3000, FI-90014 Oulu, Finland

来源：

ASTROPHYSICAL JOURNAL | 2018年 / 863卷 / 02期

基金：

芬兰科学院;

关键词：

dynamo; magnetohydrodynamics (MHD); Sun: magnetic fields; turbulence; HEMISPHERIC SIGN RULE; ACTIVE REGIONS; SCALE DYNAMO;

D O I：

10.3847/1538-4357/aad0f2

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

Using a recently developed two-scale formalism to determine the magnetic helicity spectrum, we analyze synoptic vector magnetograms built with data from the Vector Spectromagnetograph instrument on the Synoptic Optical Long-term Investigations of the Sun telescope during 2010 January-2016 July. In contrast to an earlier study using only three Carrington rotations (CRs), our analysis includes 74 synoptic CR maps. We recover here bihelical spectra at different phases of solar cycle. 24, where the net magnetic helicity in the majority of the data is consistent with a large-scale dynamo with helical turbulence operating in the Sun. More than 20% of the analyzed maps, however, show violations of the expected sign rule.

引用

页数：11

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