Benchmarking fast-to-Alfven mode conversion in a cold MHD plasma. II. How to get Alfven Waves through the solar transition region

Shelley Candice Hansen, Paul Stuart Cally

Research output: Contribution to journalArticleResearchpeer-review

27 Citations (Scopus)

Abstract

Alfven waves may be difficult to excite at the photosphere due to low-ionization fraction and suffer near-total reflection at the transition region (TR). Yet they are ubiquitous in the corona and heliosphere. To overcome these difficulties, we show that they may instead be generated high in the chromosphere by conversion from reflecting fast magnetohydrodynamic waves, and that Alfvenic TR reflection is greatly reduced if the fast reflection point is within a few scale heights of the TR. The influence of mode conversion on the phase of the reflected fast wave is also explored. This phase can potentially be misinterpreted as a travel speed perturbation with implications for the practical seismic probing of active regions.
Original languageEnglish
Pages (from-to)1 - 11
Number of pages11
JournalThe Astrophysical Journal
Volume751
Issue number1
DOIs
Publication statusPublished - 2012

Cite this

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title = "Benchmarking fast-to-Alfven mode conversion in a cold MHD plasma. II. How to get Alfven Waves through the solar transition region",
abstract = "Alfven waves may be difficult to excite at the photosphere due to low-ionization fraction and suffer near-total reflection at the transition region (TR). Yet they are ubiquitous in the corona and heliosphere. To overcome these difficulties, we show that they may instead be generated high in the chromosphere by conversion from reflecting fast magnetohydrodynamic waves, and that Alfvenic TR reflection is greatly reduced if the fast reflection point is within a few scale heights of the TR. The influence of mode conversion on the phase of the reflected fast wave is also explored. This phase can potentially be misinterpreted as a travel speed perturbation with implications for the practical seismic probing of active regions.",
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Benchmarking fast-to-Alfven mode conversion in a cold MHD plasma. II. How to get Alfven Waves through the solar transition region. / Hansen, Shelley Candice; Cally, Paul Stuart.

In: The Astrophysical Journal, Vol. 751, No. 1, 2012, p. 1 - 11.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Benchmarking fast-to-Alfven mode conversion in a cold MHD plasma. II. How to get Alfven Waves through the solar transition region

AU - Hansen, Shelley Candice

AU - Cally, Paul Stuart

PY - 2012

Y1 - 2012

N2 - Alfven waves may be difficult to excite at the photosphere due to low-ionization fraction and suffer near-total reflection at the transition region (TR). Yet they are ubiquitous in the corona and heliosphere. To overcome these difficulties, we show that they may instead be generated high in the chromosphere by conversion from reflecting fast magnetohydrodynamic waves, and that Alfvenic TR reflection is greatly reduced if the fast reflection point is within a few scale heights of the TR. The influence of mode conversion on the phase of the reflected fast wave is also explored. This phase can potentially be misinterpreted as a travel speed perturbation with implications for the practical seismic probing of active regions.

AB - Alfven waves may be difficult to excite at the photosphere due to low-ionization fraction and suffer near-total reflection at the transition region (TR). Yet they are ubiquitous in the corona and heliosphere. To overcome these difficulties, we show that they may instead be generated high in the chromosphere by conversion from reflecting fast magnetohydrodynamic waves, and that Alfvenic TR reflection is greatly reduced if the fast reflection point is within a few scale heights of the TR. The influence of mode conversion on the phase of the reflected fast wave is also explored. This phase can potentially be misinterpreted as a travel speed perturbation with implications for the practical seismic probing of active regions.

UR - http://iopscience.iop.org/0004-637X/751/1/31/

U2 - 10.1088/0004-637X/751/1/31

DO - 10.1088/0004-637X/751/1/31

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JO - The Astrophysical Journal

JF - The Astrophysical Journal

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