HIGH-RESOLUTION OBSERVATIONS of A LARGE FAN-SHAPED SURGE

Document Type

Article

Publication Date

8-1-2016

Abstract

We present high-resolution observations of a large fan-shaped surge, which was observed on 2013 June 5 with the current largest solar telescope, the 1.6 m New Solar Telescope (NST), at the Big Bear Solar Observatory. The observations are made at TiO, Hα, and 10830 - wavebands with a spatial resolution better than and a full-run cadence of ∼30 s. The fan-shaped surge consists of many small-scale threads with a typical width of 100 km and a length of up to 200 Mm at the maximum. The threads come from material ejections, which start with a velocity of several km s-1, and then accelerate up to 60-80 km s-1 over six to seven minutes with an acceleration of up to 0.2-0.3 km s-2. The threads can be observed in the Hα band and in SDO/AIA 171 - images as absorbed objects, implying that they are cool material ejections. The surge is ejected along open magnetic field lines in the extrapolated non-linear force-free field, which might actually be a part of a large-scale magnetic loop stretching back to the solar surface. After 10-20 minutes, the ejections gradually decay and the surge eventually vanishes. The total lifetime is about 35 minutes. The Hα brightening at the root of the fan-shaped surge implies that there is heating in the chromosphere, which could be produced by low-atmosphere interchange magnetic reconnection. Our observation provides evidence of the reconnection model for the fan-shaped surges, which was proposed by Jiang et al.

Identifier

84982224382 (Scopus)

Publication Title

Astrophysical Journal

External Full Text Location

https://doi.org/10.3847/0004-637X/826/2/217

e-ISSN

15384357

ISSN

0004637X

Issue

2

Volume

826

Grant

2011CB811402

Fund Ref

National Science Foundation

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