Identification

Title

A solar tornado triggered by flares

Abstract

Context. Solar tornados are dynamical, conspicuously helical magnetic structures that are mainly observed as a prominence activity. Aims. We investigate and propose a triggering mechanism for the solar tornado observed in a prominence cavity by SDO/AIA on September 25, 2011. Methods. High-cadence EUV images from the SDO/AIA and the Ahead spacecraft of STEREO/EUVI are used to correlate three flares in the neighbouring active-region (NOAA 11303) and their EUV waves with the dynamical developments of the tornado. The timings of the flares and EUV waves observed on-disk in 195 Å are analysed in relation to the tornado activities observed at the limb in 171 Å. Results. Each of the three flares and its related EUV wave occurred within ten hours of the onset of the tornado. They have an observed causal relationship with the commencement of activity in the prominence where the tornado develops. Tornado-like rotations along the side of the prominence start after the second flare. The prominence cavity expands with the accelerating tornado motion after the third flare. Conclusions. Flares in the neighbouring active region may have affected the cavity prominence system and triggered the solar tornado. A plausible mechanism is that the active-region coronal field contracted by the "Hudson effect" through the loss of magnetic energy as flares. Subsequently, the cavity expanded by its magnetic pressure to fill the surrounding low corona. We suggest that the tornado is the dynamical response of the helical prominence field to the cavity expansion.

Resource type

document

Resource locator

Unique resource identifier

code

http://n2t.net/ark:/85065/d70c4wkt

codeSpace

Dataset language

eng

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code identifying the spatial reference system

Classification of spatial data and services

Topic category

geoscientificInformation

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keyword value

Text

originating controlled vocabulary

title

Resource Type

reference date

date type

publication

effective date

2016-01-01T00:00:00Z

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East bounding longitude

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End position

Dataset reference date

date type

publication

effective date

2013-01-01T00:00:00Z

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Limitations on public access

None

Responsible organisations

Responsible party

contact position

OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

responsible party role

pointOfContact

Metadata on metadata

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