Long-Term Solar Variability (LSV) Section
–16 October 2012–
Coronal Cavity Research in the News: Analyses of solar coronal prominence cavities by an international group of scientists including HAO's Sarah Gibson, Christian Bethge, Giuliana de Toma, Yuhong Fan, HAO visitor Urszula Bak Steslicka and University of Colorado graduate student Don Schmit, has been profiled in a NASA news release and UCAR AtmosNews research brief. Cavities ultimately may erupt as coronal mass ejections (CMEs), but only after days or weeks of existence as a strikingly organized, elliptical coronal structure. Probing the physical properties of prominence cavities provides clues to the magnetohydrodynamic equilibrium states that precede a CME. The NASA news release described a three-paper series by an international team of researchers that quantifies the morphological, density, and temperature structure within a coronal prominence cavity (Gibson et al., 2010; Schmit and Gibson, 2011; Kucera et al., 2012). UCAR AtmosNews highlighted new cavity observations from HAO's CoMP telescope which are providing evidence for the presence of twisted magnetic fields in the corona. See story in UCAR's AtmosNews ». Also see NASA » story.
–1 May 2012–
HAO graduate fellow Maria Weber has been selected to receive an AGU Outstanding Student Paper Award for her talk titled, "Comparing simulations of rising flux tubes through the solar convection zone with observations of active region properties: Constraining the dynamo field strength", presented at the 2011 Fall AGU meeting in San Francisco. The AGU talk announcements appear in the premier international newspaper of the Earth and Space Sciences, EOS (Vol. 93, Number 31, 31 July 2012).
Figure Caption: Snapshot of a thin flux tube simulation in a rotating spherical shell of solar-like giant cell convection.
–March 9, 2012–
Recent work on historical recurrent geomagnetic activity and the peculiarity of the recent solar-cycle minimum, led by US Geological Survey's Jeff Love and co-authored by Josh Rigler (USGS) and Sarah Gibson (HAO), was chosen by the editors of AGU journals for special highlight. Electronic File »
Geophysical Research Letters »
Figure Caption: Stackplot of solar-terrestrial data and comparison with the geomagnetic-activity aa index for 2006, Carrington rotations 2044–2049. Vertical lines denote 6.7-d increments.
–February 6, 2012–
HAO solar science is featured in a new article on NCAR/UCAR "AtmosNews". The article profiles the efforts to study and connect the solar dynamo and magnetic flux emergence by Mark Miesch and colleagues Ben Brown (Univeristy of Wisconsin-Madison), Nick Nelson and Juri Toomre (University of Colorado-Boulder), and Allan Sacha Brun (National Center for Scientific Research, France). This work contributes significantly to HAO's Frontier 4, "Link Dynamos to Simulations of Flux Emergence". AtmosNews »
Figure Caption: New simulations of a star much like the Sun, but rotating five times faster, produce wreaths of magnetism in each hemisphere.
–04 January 2012–
HAO scientist's Mausumi Dikpati, Peter Gilman, Giuliana de Toma, and UCLA professor Roger Ulrich find that the latitude at which plasma sinking occurs is very important. LiveScience »
Figure Caption: Simulations of the conditions below the sun's surface yielded this two dimensional map of a cycle-period for the solar dynamo, the physical process that generates the sun's magnetic field. The thick, continuous white line denotes the 11-year-cycle period. Thin white lines are other periods in half-year intervals and the horizontal broken line marks the maximum magnetic flux. Solar cycles 22 and 23 in this map are semi-transparent gray patches. CREDIT: Mausumi Dikpati and UCAR.
The December, 2011 issue of Solar Physics was a Topical Issue on the Sun-Earth Connection near Solar Minimum [web link], presenting articles based on studies ranging around the recent solar minimum, and more specifically, studies of the Whole Heliosphere Interval (WHI). [web link]. WHI was an internationally coordinated observation-and-modeling effort to characterize the three-dimensional (3D) heliosphere and the Sun-planet connectivity during solar minimum. WHI was the largest oordinated Investigation Program (CIP) of the International Heliophysical Year (IHY) (2007–2009), which was inspired by the 50th Anniversary of the International Geophysical Year (IGY) (1957–1958) and the subsequent 50 years of space exploration. This Topical Issue was edited by HAO scientist Barbara Emery, along with Mario Bisi from Aberystwyth University (Wales) and Barbara Thompson from NASA Goddard. Papers included contributions from HAO authors de Toma, Emery, Gibson, McIntosh, Qian, Solomon, Wang, Wiltberger, and Zhao.