Issue |
A&A
Volume 553, May 2013
|
|
---|---|---|
Article Number | A100 | |
Number of page(s) | 9 | |
Section | The Sun | |
DOI | https://doi.org/10.1051/0004-6361/201220319 | |
Published online | 16 May 2013 |
Radial profile of the inner heliospheric magnetic field as deduced from Faraday rotation observations
1
INAF – Osservatorio Astrofisico di Torino, Strada Osservatorio 20, 10025
Pino Torinese,
Italy
e-mail: mancuso@oato.inaf.it
2
Laboratory for Astroparticle Physics, University of Nova
Gorica, 5000
Nova Gorica,
Slovenia
Received:
31
August
2012
Accepted:
27
March
2013
Faraday rotation measures (RMs) of the polarized emission from extragalactic radio sources occulted by the coronal plasma were used to infer the radial profile of the inner heliospheric magnetic field near the solar minimum. By inverting LASCO/SOHO polarized brightness (pB) data taken during the observations in May 1997, we retrieved the electron density distribution along the lines of sight to the sources, which allowed us to separate the two plasma properties that contribute to the observed RMs. By comparing the observed RM values with those theoretically predicted by a power law model of the radial component of the coronal magnetic field using a best-fitting procedure, we found that the radial component of the inner heliospheric magnetic field can be nicely approximated by a power law of the form Br = 3.76 r-2.29 G in a range of heights from about 5 to 14 R⊙. Finally, our analysis suggests that the radial computation of the potential field source surface model from the Wilcox Solar Observatory is the preferred choice near solar minimum assuming a radial field in the photosphere and a source surface located at Rss = 2.5 R⊙.
Key words: Sun: corona / Sun: magnetic topology / Sun: radio radiation
© ESO, 2013
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.