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SWAN/SOHO Lyman-α Mapping: The Hydrogen Geocorona Extends Well Beyond the Moon
Schmidt, W.; Bertaux, J. -L.; Quémerais, E. +2 more
The Earth's hydrogen exosphere Lyman-α radiation was mapped with the Solar Wind Anisotropies/Solar and Heliospheric Observatory (SWAN/SOHO) instrument in January 1996, 1997, and 1998 (low solar activity). The use of a hydrogen absorption cell allowed to disentangle the interplanetary emission from the geocoronal one and to assign the absorbed sign…
Statistical Study on Multispacecraft Widespread Solar Energetic Particle Events During Solar Cycle 24
St. Cyr, O. C.; Gopalswamy, N.; Mäkelä, P. +1 more
We conduct a statistical study on the large three-spacecraft widespread solar energetic particle (SEP) events. Longitudinal distributions of the peak intensities, onset delays, and relation between the SEP intensity, coronal mass ejection (CME) shock speed, width, and the kinetic energy of the CME have been investigated. We apply a Gaussian fit to…
Radio Occultation Observations of the Solar Corona Over 1.60-1.86 R⊙: Faraday Rotation and Frequency Shift Analysis
Lionello, Roberto; Hollweg, Joseph V.; Jensen, Elizabeth A. +5 more
The study of coronal energy transport, central to the solar wind acceleration problem, relies upon accurate representation of magnetic fields and plasma electron densities. This information is difficult to obtain in middle-to-lower coronal regions that may contain complex magnetic structures. Faraday rotation (FR) solar radio occultation observati…
Multiple Scattering Effects in the Interplanetary Medium: Evaluation Using SOHO SWAN and MAVEN EUVM Lyman α Measurements
Quémerais, Eric; Schmidt, Walter; Thiemann, Edward +2 more
Interplanetary background measurements can be used to derive the solar flux that is illuminating the atoms in the interplanetary medium. We present a new algorithm combining measurements from the Solar Wind ANisotropies (SWAN)-Solar Heliospheric Observatory (SOHO) Lyman α photometer with Earth-based solar flux measurements to derive the solar illu…
Investigation of a Confined C-Class Flare in an Arch Filament System Close to a Regular Sunspot
Louis, Rohan Eugene
A moderate C1.1 class confined flare is investigated here, which occurred on 24 September 2013 at 22:56 UT, in an arch filament system close to a regular, unipolar sunspot. Spectropolarimetric observations from the Tenerife Infrared Polarimeter at the 70-cm German Vacuum Tower Telescope were combined with data from the Helioseismic Magnetic Imager…