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Title: GROUND LEVEL ENHANCEMENT IN THE 2014 JANUARY 6 SOLAR ENERGETIC PARTICLE EVENT

Abstract

We present a study of the 2014 January 6 solar energetic particle event which produced a small ground level enhancement (GLE), making it the second GLE of this unusual solar cycle 24. This event was primarily observed by the South Pole neutron monitors (increase of ∼2.5%) while a few other neutron monitors recorded smaller increases. The associated coronal mass ejection (CME) originated behind the western limb and had a speed of 1960 km s{sup –1}. The height of the CME at the start of the associated metric type II radio burst, which indicates the formation of a strong shock, was measured to be 1.61 Rs using a direct image from STEREO-A/EUVI. The CME height at the time of the GLE particle release (determined using the South Pole neutron monitor data) was directly measured as 2.96 Rs based on STEREO-A/COR1 white-light observations. These CME heights are consistent with those obtained for GLE71, the only other GLE of the current cycle, as well as cycle-23 GLEs derived using back-extrapolation. GLE72 is of special interest because it is one of only two GLEs of cycle 24, one of two behind-the-limb GLEs, and one of the two smallest GLEs of cycles 23 and 24.

Authors:
; ; ; ; ; ;  [1]
  1. NASA Goddard Space Flight Center, Greenbelt, MD (United States)
Publication Date:
OSTI Identifier:
22365533
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 790; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCELERATION; EXTRAPOLATION; MASS; NEUTRON MONITORS; SHOCK WAVES; SOLAR CORONA; SOLAR CYCLE; SUN; VELOCITY; VISIBLE RADIATION

Citation Formats

Thakur, N., Gopalswamy, N., Xie, H., Mäkelä, P., Yashiro, S., Akiyama, S., and Davila, J. M. GROUND LEVEL ENHANCEMENT IN THE 2014 JANUARY 6 SOLAR ENERGETIC PARTICLE EVENT. United States: N. p., 2014. Web. doi:10.1088/2041-8205/790/1/L13.
Thakur, N., Gopalswamy, N., Xie, H., Mäkelä, P., Yashiro, S., Akiyama, S., & Davila, J. M. GROUND LEVEL ENHANCEMENT IN THE 2014 JANUARY 6 SOLAR ENERGETIC PARTICLE EVENT. United States. doi:10.1088/2041-8205/790/1/L13.
Thakur, N., Gopalswamy, N., Xie, H., Mäkelä, P., Yashiro, S., Akiyama, S., and Davila, J. M. Sun . "GROUND LEVEL ENHANCEMENT IN THE 2014 JANUARY 6 SOLAR ENERGETIC PARTICLE EVENT". United States. doi:10.1088/2041-8205/790/1/L13.
@article{osti_22365533,
title = {GROUND LEVEL ENHANCEMENT IN THE 2014 JANUARY 6 SOLAR ENERGETIC PARTICLE EVENT},
author = {Thakur, N. and Gopalswamy, N. and Xie, H. and Mäkelä, P. and Yashiro, S. and Akiyama, S. and Davila, J. M.},
abstractNote = {We present a study of the 2014 January 6 solar energetic particle event which produced a small ground level enhancement (GLE), making it the second GLE of this unusual solar cycle 24. This event was primarily observed by the South Pole neutron monitors (increase of ∼2.5%) while a few other neutron monitors recorded smaller increases. The associated coronal mass ejection (CME) originated behind the western limb and had a speed of 1960 km s{sup –1}. The height of the CME at the start of the associated metric type II radio burst, which indicates the formation of a strong shock, was measured to be 1.61 Rs using a direct image from STEREO-A/EUVI. The CME height at the time of the GLE particle release (determined using the South Pole neutron monitor data) was directly measured as 2.96 Rs based on STEREO-A/COR1 white-light observations. These CME heights are consistent with those obtained for GLE71, the only other GLE of the current cycle, as well as cycle-23 GLEs derived using back-extrapolation. GLE72 is of special interest because it is one of only two GLEs of cycle 24, one of two behind-the-limb GLEs, and one of the two smallest GLEs of cycles 23 and 24.},
doi = {10.1088/2041-8205/790/1/L13},
journal = {Astrophysical Journal Letters},
number = 1,
volume = 790,
place = {United States},
year = {Sun Jul 20 00:00:00 EDT 2014},
month = {Sun Jul 20 00:00:00 EDT 2014}
}