Periodicity of twisting motions in sunspot penumbral filaments

Document Type

Article

Publication Date

7-1-2009

Abstract

We study the periodicity of twisting motions in sunspot penumbral filaments, which were recently discovered from space (Hinode) and ground-based (SST) observations. A sunspot was well observed for 97 minutes by Hinode/SOT in the G-band (4305 Å) on 12 November 2006. By the use of the time-space gradient applied to intensity space-time plots, twisting structures can be identified in the penumbral filaments. Consistent with previous findings, we find that the twisting is oriented from the solar limb to disk center. Some of them show a periodicity. The typical period is about ≈four minutes, and the twisting velocity is roughly 6 km s-1. However, the penumbral filaments do not always show periodic twisting motions during the time interval of the observations. Such behavior seems to start and stop randomly with various penumbral filaments displaying periodic twisting during different intervals. The maximum number of periodic twists is 20 in our observations. Studying this periodicity can help us to understand the physical nature of the twisting motions. The present results enable us to determine observational constraints on the twisting mechanism. © 2009 Springer Science+Business Media B.V.

Identifier

67650682934 (Scopus)

Publication Title

Solar Physics

External Full Text Location

https://doi.org/10.1007/s11207-009-9373-2

e-ISSN

1573093X

ISSN

00380938

First Page

251

Last Page

260

Issue

2

Volume

257

Grant

0847126

Fund Ref

National Science Foundation

This document is currently not available here.

Share

COinS