NDLI: Interplanetary Signatures of Unipolar Streamers and the Origin of the Slow Solar Wind

Content Provider	Springer Nature Link
Author	Riley, P. Luhmann, J. G.
Copyright Year	2011
Abstract	Unipolar streamers (also known as pseudo-streamers) are coronal structures that, at least in coronagraph images, and when viewed at the correct orientation, are often indistinguishable from dipolar (or “standard”) streamers. When interpreted with the aid of a coronal magnetic field model, however, they are shown to consist of a pair of loop arcades. Whereas dipolar streamers separate coronal holes of the opposite polarity and whose cusp is the origin of the heliospheric current sheet, unipolar streamers separate coronal holes of the same polarity and are therefore not associated with a current sheet. In this study, we investigate the interplanetary signatures of unipolar streamers. Using a global MHD model of the solar corona driven by the observed photospheric magnetic field for Carrington rotation 2060, we map the ACE trajectory back to the Sun. The results suggest that ACE fortuitously traversed through a large and well-defined unipolar streamer. We also compare heliospheric model results at 1 AU with ACE in-situ measurements for Carrington rotation 2060. The results strongly suggest that the solar wind associated with unipolar streamers is slow. We also compare predictions using the original Wang–Sheeley (WS) empirically determined inverse relationship between solar wind speed and expansion factor. Because of the very low expansion factors associated with unipolar streamers, the WS model predicts high speeds, in disagreement with the observations. We discuss the implications of these results in terms of theories for the origin of the slow solar wind. Specifically, premises relying on the expansion factor of coronal flux tubes to modulate the properties of the plasma (and speed, in particular) must address the issue that while the coronal expansion factors are significantly different at dipolar and unipolar streamers, the properties of the measured solar wind are, at least qualitatively, very similar.
Starting Page	355
Ending Page	373
Page Count	19
File Format	PDF
ISSN	00380938
Journal	Solar Physics
Volume Number	277
Issue Number	2
e-ISSN	1573093X
Language	English
Publisher	Springer Netherlands
Publisher Date	2011-12-16
Publisher Place	Dordrecht
Access Restriction	One Nation One Subscription (ONOS)
Subject Keyword	Interplanetary medium Solar wind Sun: corona, evolution, magnetic fields Meteorology/Climatology Astrophysics and Astroparticles Extraterrestrial Physics, Space Sciences
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

Mapping Solar Wind Streams from the Sun to 1 AU: A Comparison of Techniques

Global MHD Modeling of the Solar Corona and Inner Heliosphere for the Whole Heliosphere Interval

Slow-Mode Oscillations and Damping of Hot Solar Coronal Loops

Correlation Functions of Small-Scale Fluctuations of the Interplanetary Magnetic Field

Faraday Rotation Response to Coronal Mass Ejection Structure

On Rotation of the Solar Corona

High-Latitude Inner Solar Wind from Pulsar Radio Sounding Observations

Latitudinal structure and north-south asymmetry of the solar wind from Lyman-α remote sensing by SWAN

A Multi-Observatory Inter-Comparison of Line-of-Sight Synoptic Solar Magnetograms

Interplanetary Signatures of Unipolar Streamers and the Origin of the Slow Solar Wind

Similar Documents

Mapping Solar Wind Streams from the Sun to 1 AU: A Comparison of Techniques

Global MHD Modeling of the Solar Corona and Inner Heliosphere for the Whole Heliosphere Interval

Slow-Mode Oscillations and Damping of Hot Solar Coronal Loops

Correlation Functions of Small-Scale Fluctuations of the Interplanetary Magnetic Field

Faraday Rotation Response to Coronal Mass Ejection Structure

On Rotation of the Solar Corona

High-Latitude Inner Solar Wind from Pulsar Radio Sounding Observations

Latitudinal structure and north-south asymmetry of the solar wind from Lyman-α remote sensing by SWAN

A Multi-Observatory Inter-Comparison of Line-of-Sight Synoptic Solar Magnetograms

Interplanetary Signatures of Unipolar Streamers and the Origin of the Slow Solar Wind