A Change in the Solar He ii EUV Global Network Structure as an Indicator of the Geo-Effectiveness of Solar Minima

Didkovsky, L.; Gurman, J. B.
January 2014
Solar Physics;Jan2014, Vol. 289 Issue 1, p153
Academic Journal
Solar activity during 2007 – 2009 was very low, causing anomalously low thermospheric density. A comparison of solar extreme ultraviolet (EUV) irradiance in the He  ii spectral band (26 to 34 nm) from the Solar Extreme ultraviolet Monitor (SEM), one of instruments on the Charge Element and Isotope Analysis System (CELIAS) on board the Solar and Heliospheric Observatory (SOHO) for the two latest solar minima showed a decrease of the absolute irradiance of about 15±6 % during the solar minimum between Cycles 23 and 24 compared with the Cycle 22/23 minimum when a yearly running-mean filter was used. We found that some local, shorter-term minima including those with the same absolute EUV flux in the SEM spectral band show a higher concentration of spatial power in the global network structure from the 30.4 nm SOHO/ Extreme ultraviolet Imaging Telescope (EIT) images for the local minimum of 1996 compared with the minima of 2008 – 2011. We interpret this higher concentration of spatial power in the transition region’s global network structure as a larger number of larger-area features on the solar disk. These changes in the global network structure during solar minima may characterize, in part, the geo-effectiveness of the solar He  ii EUV irradiance in addition to the estimations based on its absolute levels.


Related Articles

  • The Plate Scale of the SODISM Instrument and the Determination of the Solar Radius at 607.1 nm. Meftah, M.; Hauchecorne, A.; Crepel, M.; Irbah, A.; Corbard, T.; Djafer, D.; Hochedez, J.-F. // Solar Physics;Jan2014, Vol. 289 Issue 1, p1 

    Knowledge of the Solar Diameter Imager and Surface Mapper (SODISM) plate scale is a fundamental parameter for obtaining the solar radius. We have determined the plate scale of the telescope on the ground and in flight onboard the Picard spacecraft. The results show significant differences; the...

  • STEREO/Extreme Ultraviolet Imager (EUVI) Event Catalog 2006 – 2012. Aschwanden, Markus J.; Wülser, Jean-Pierre; Nitta, Nariaki V.; Lemen, James R.; Freeland, Sam; Thompson, William T. // Solar Physics;Mar2014, Vol. 289 Issue 3, p919 

    We generated an event catalog with an automated detection algorithm based on the entire EUVI image database observed with the two Solar Terrestrial Relations Observatory (STEREO)-A and -B spacecraft over the first six years of the mission (2006 – 2012). The event catalog...

  • Exploring the Sun. Ramsden, Stephen W.; MacRobert, Alan // Sky Watch (1089-4888);2013, p50 

    The article presents tips on watching the sun during the peak of solar activity. Topics covered include the damages that using telescope can do to skywatchers when viewing the sun at this time. Also mentioned are the harmful effects of infrared and ultraviolet rays on skyviewers as well as the...

  • The Association of Solar Flares with Coronal Mass Ejections During the Extended Solar Minimum. Nitta, N. V.; Aschwanden, M. J.; Freeland, S. L.; Lemen, J. R.; Wülser, J.-P.; Zarro, D. M. // Solar Physics;Apr2014, Vol. 289 Issue 4, p1257 

    We study the association of solar flares with coronal mass ejections (CMEs) during the deep, extended solar minimum of 2007 – 2009, using extreme-ultraviolet (EUV) and white-light (coronagraph) images from the Solar Terrestrial Relations Observatory (STEREO). Although all of...

  • World news roundup.  // Aviation Week & Space Technology;3/15/1999, Vol. 150 Issue 11, p21 

    Details the research showing how to predict solar disruptions days before they hit Earth. Effect of solar disruptions on satellites, power grids, navigation aids and electronics; Use of imagery from the Soft X-ray Telescope on Japan's Yokoh spacecraft; Formation of an S-shaped pattern on the...

  • Teoretical nonstationary two-dimensional modal with altitude-longitudinal variations of ionosphere parameters. Bogomolova, Mariya; Ishanov, Sergey; Klevtsur, Sergey; Kozhurova, Alla; Latyshev, Konstantin // Vestnik IKBFU;2013, Issue 10, p14 

    By means of mathematical two-dimensional nonstationary model mechanisms of formation of longitudinal effect in a middle-latitude ionosphere are probed and is shown that one of main engines is the thermosphere wind in combination with earth magnetic field geometry. Model calculations of...

  • Some features of nighttime enhancements in the electron concentration in the F2-layer maximum of the midlatitude ionosphere. Yakovets, A.; Vodyannikov, V.; Gordienko, G.; Litvinov, Yu. // Geomagnetism & Aeronomy;Nov2014, Vol. 54 Issue 6, p791 

    Using the data of vertical sounding of the ionosphere in Alma-Ata (76°55′ E, 43°15′ N) conducted in 2002-2012, the reaction of parameters of the ionospheric F2 layer to various types of nighttime enhancements in the electron concentration in the maximum of the layer ( NmF2) was...

  • Solar Section. Beales, Mike // Journal of the British Astronomical Association;Dec2004, Vol. 114 Issue 6, p310 

    Reports on the sunspot activity in July 2004. Change from low to high activity state; Appearance of a spot at N08/350 on the E limb on July 16.

  • David Newnham is star struck by the power of a supernova.  // Nursing Standard;1/12/2005, Vol. 19 Issue 18, p24 

    The article reports on the future of the sun. When the sun dies after five billion years from the twenty-first century, it will puff itself into a monstrous red giant before shrinking back into a dense ball no larger than the earth. This unimaginable performance will incinerate the entire solar...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics