NDLI: Helicity Patterns of the Active Regions Connected by Transequatorial Loops

Content Provider	Springer Nature Link
Author	Chen, Jie Bao, Shudong Zhang, Hongqi
Copyright Year	2007
Abstract	Using photospheric vector magnetograms of the Huairou Solar Observing Station and coronal X-ray images from the Yohkoh Soft X-Ray Telescope, we calculate the helicity patterns of 43 pairs of active regions and the chirality of 50 pairs of opposite magnetic polarity regions that are connected by transequatorial loops (TLs). To make the results more convincing, two helicity proxies including the local current helicity h $_{c}$ and the force-free factor α $_{best}$ are computed. The results, which are similar for both parameters, are as follows: (1) Current helicity of the active regions pairs connected by transequatorial loops have no obvious regularity: About 50% of the active region pairs carry the same current helicity sign and about 50% of them have the opposite. (2) If we consider the magnetic polarity pairs connected by the TLs, the result is almost the same as that for the active region pairs, with a little more than half of them showing the same chirality. We also make linear force-free extrapolations for 33 TLs and determine their force-free parameter α by comparing extrapolated field lines to X-ray images of the TLs. Out of the 19 cases when the footpoints of the TLs have the same current helicity sign, we find that the sign of α of the TLs is the same as the sign of the current helicity in the footpoints in 12 cases, whereas it is of opposite sign in 4 cases, and in 3 cases the TLs were found to be potential.
Starting Page	65
Ending Page	85
Page Count	21
File Format	PDF
ISSN	00380938
Journal	Solar Physics
Volume Number	242
Issue Number	1-2
e-ISSN	1573093X
Language	English
Publisher	Springer Netherlands
Publisher Date	2007-06-01
Publisher Place	Dordrecht
Access Restriction	One Nation One Subscription (ONOS)
Subject Keyword	Astronomy Extraterrestrial Physics, Space Sciences Astrophysics
Content Type	Text
Resource Type	Article
Subject	Astronomy and Astrophysics Space and Planetary Science

Sl.	Authority	Responsibilities	Communication Details
1	Ministry of Education (GoI), Department of Higher Education	Sanctioning Authority	https://www.education.gov.in/ict-initiatives
2	Indian Institute of Technology Kharagpur	Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project	https://www.iitkgp.ac.in
3	National Digital Library of India Office, Indian Institute of Technology Kharagpur	The administrative and infrastructural headquarters of the project	Dr. B. Sutradhar bsutra@ndl.gov.in
4	Project PI / Joint PI	Principal Investigator and Joint Principal Investigators of the project	Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon
5	Website/Portal (Helpdesk)	Queries regarding NDLI and its services	support@ndl.gov.in
6	Contents and Copyright Issues	Queries related to content curation and copyright issues	content@ndl.gov.in
7	National Digital Library of India Club (NDLI Club)	Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach	clubsupport@ndl.gov.in
8	Digital Preservation Centre (DPC)	Assistance with digitizing and archiving copyright-free printed books	dpc@ndl.gov.in
9	IDR Setup or Support	Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops	idr@ndl.gov.in

A Statistical Study of Transequatorial Loops

Evidence of Twisted Flux-Tube Emergence in Active Regions

Cme Associated with Transequatorial Loops and a Bald Patch Flare

Determination of the True Shape of Coronal Loops

Active Regions with Superpenumbral Whirls and Their Subsurface Kinetic Helicity

Photospheric Injection of Magnetic Helicity: Connectivity-Based Flux Density Method

Properties of Magnetic Tongues over a Solar Cycle

Active-Region Twist Derived from Magnetic Tongues and Linear Force-Free Extrapolations

Photospheric Magnetic Evolution in the WHI Active Regions

Helicity Patterns of the Active Regions Connected by Transequatorial Loops

Similar Documents

A Statistical Study of Transequatorial Loops

Evidence of Twisted Flux-Tube Emergence in Active Regions

Cme Associated with Transequatorial Loops and a Bald Patch Flare

Determination of the True Shape of Coronal Loops

Active Regions with Superpenumbral Whirls and Their Subsurface Kinetic Helicity

Photospheric Injection of Magnetic Helicity: Connectivity-Based Flux Density Method

Properties of Magnetic Tongues over a Solar Cycle

Active-Region Twist Derived from Magnetic Tongues and Linear Force-Free Extrapolations

Photospheric Magnetic Evolution in the WHI Active Regions

Helicity Patterns of the Active Regions Connected by Transequatorial Loops