Author ORCID Identifier

James McAteer:
https://orcid.org/0000-0003-1493-101X

Jason Jackiewicz:
https://orcid.org/0000-0001-9659-7486

Ryan Milligan:
https://orcid.org/0000-0001-5031-1892

Krishnan Balasubramaniam:
https://orcid.org/0000-0003-2221-0933

Document Type

Journal Article

Journal Article Version

Final Version / Publisher's PDF (peer-reviewed)

Publication Date

5-10-2012

Abstract

We report on the physical properties of solar sequential chromospheric brightenings (SCBs) observed in conjunction with moderate-sized chromospheric flares with associated Coronal mass ejections. To characterize these ephemeral events, we developed automated procedures to identify and track subsections (kernels) of solar flares and associated SCBs using high-resolution Ha images. Following the algorithmic identification and a statistical analysis, we compare and find the following: SCBs are distinctly different from flare kernels in their temporal characteristics of intensity, Doppler structure, duration, and location properties. We demonstrate that flare ribbons are themselves made up of subsections exhibiting differing characteristics. Flare kernels are measured to have a mean propagation speed of 0.2 km s(-1) and a maximum speed of 2.3 km s(-1) over a mean distance of 5 x 10(3) km. Within the studied population of SCBs, different classes of characteristics are observed with coincident negative, positive, or both negative and positive Doppler shifts of a few km s-1. The appearance of SCBs precedes peak flare intensity by approximate to 12 minutes and decay approximate to 1 hr later. They are also found to propagate laterally away from flare center in clusters at 45 km s(-1) or 117 km s(-1). Given SCBs' distinctive nature compared to flares, we suggest a different physical mechanism relating to their origin than the associated flare. We present a heuristic model of the origin of SCBs.

Published in

Astrophysical Journal

DOI

10.1088/0004-637X/750/2/145

Keywords

Sun: flares, Sun: chromosphere

Department / Organizational Unit

Astronomy

License for Reuse

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

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