Advanced search
Start date
Betweenand
Related content
(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Latitude-dependent delay in the responses of the equatorial electrojet and S-q currents to X-class solar flares

Full text
Author(s):
Nogueira, Paulo A. B. [1] ; Abdu, Mangalathayil A. [2] ; Souza, Jonas R. [2] ; Denardini, Clezio M. [2, 3] ; Barbosa Neto, Paulo F. [2, 3] ; Serra de Souza da Costa, Joao P. [1] ; Silva, Ana P. M. [1]
Total Authors: 7
Affiliation:
[1] Fed Inst Educ Sci & Technol Sao Paulo, Sao Paulo - Brazil
[2] Inst Nacl Pesquisas Espaciais, Div Aeron, BR-12227010 Sao Jose Dos Campos, SP - Brazil
[3] Inst Nacl Pesquisas Espaciais, Embrace Space Weather Program, BR-12227010 Sao Jose Dos Campos, SP - Brazil
Total Affiliations: 3
Document type: Journal article
Source: Annales Geophysicae; v. 36, n. 1, p. 139-147, JAN 25 2018.
Web of Science Citations: 2
Abstract

Ionosphere (equatorial ionosphere)We have analyzed low-latitude ionospheric current responses to two intense (X-class) solar flares that occurred on 13 May 2013 and 11 March 2015. Sudden intensifications, in response to solar flare radiation impulses, in the S-q and equatorial electrojet (EEJ) currents, as detected by magnetometers over equatorial and low-latitude sites in South America, are studied. In particular we show for the first time that a 5 to 8 min time delay is present in the peak effect in the EEJ, with respect that of S-q current outside the magnetic equator, in response to the flare radiation enhancement. The S-q current intensification peaks close to the flare X-ray peak, while the EEJ peak occurs 5 to 8 min later. We have used the Sheffield University Plasmasphere-Ionosphere Model at National Institute for Space Research (SUPIM-INPE) to simulate the E-region conductivity enhancement as caused by the flare enhanced solar extreme ultraviolet (EUV) and soft X-rays flux. We propose that the flare-induced enhancement in neutral wind occurring with a time delay (with respect to the flare radiation) could be responsible for a delayed zonal electric field disturbance driving the EEJ, in which the Cowling conductivity offers enhanced sensitivity to the driving zonal electric field. (AU)

FAPESP's process: 12/08445-9 - Study of day-to-day variability of the mesosphere, thermosphere and ionosphere at low latitude and equatorial region, during the solar cycle 24
Grantee:Paulo Roberto Fagundes
Support type: Research Projects - Thematic Grants