Search Publications
Comparison of Line-of-Sight Magnetograms Taken by the Solar Dynamics Observatory/Helioseismic and Magnetic Imager and Solar and Heliospheric Observatory/Michelson Doppler Imager
Liu, Y.; Sun, X.; Hoeksema, J. T. +7 more
We compare line-of-sight magnetograms from the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO) and the Michelson Doppler Imager (MDI) onboard the Solar and Heliospheric Observatory (SOHO). The line-of-sight magnetic signal inferred from the calibrated MDI data is greater than that derived from the HMI data by a …
The Large Longitudinal Spread of Solar Energetic Particles During the 17 January 2010 Solar Event
Gómez-Herrero, R.; Dresing, N.; Heber, B. +3 more
We investigate multi-spacecraft observations of the 17 January 2010 solar energetic particle event. Energetic electrons and protons have been observed over a remarkable large longitudinal range at the two STEREO spacecraft and SOHO, suggesting a longitudinal spread of nearly 360 degrees at 1 AU. The flaring active region, which was on the backside…
On the Nature and Genesis of EUV Waves: A Synthesis of Observations from SOHO, STEREO, SDO, and Hinode (Invited Review)
Vourlidas, Angelos; Patsourakos, Spiros
A major, albeit serendipitous, discovery of the SOlar and Heliospheric Observatory mission was the observation by the Extreme Ultraviolet Telescope (EIT) of large-scale extreme ultraviolet (EUV) intensity fronts propagating over a significant fraction of the Sun's surface. These so-called EIT or EUV waves are associated with eruptive phenomena and…
Computer Vision for the Solar Dynamics Observatory (SDO)
Wiegelmann, T.; Hochedez, J. F.; Raouafi, N. -E. +22 more
In Fall 2008 NASA selected a large international consortium to produce a comprehensive automated feature-recognition system for the Solar Dynamics Observatory (SDO). The SDO data that we consider are all of the Atmospheric Imaging Assembly (AIA) images plus surface magnetic-field images from the Helioseismic and Magnetic Imager (HMI). We produce r…
Relation Between Coronal Hole Areas on the Sun and the Solar Wind Parameters at 1 AU
Temmer, M.; Veronig, A. M.; Vršnak, B. +1 more
We analyze the relationship between the coronal hole (CH) characteristics on the Sun (area, position, and intensity levels) and the corresponding solar wind parameters (solar wind speed v, proton temperature T, proton density n, and magnetic field strength B) measured in situ at 1 AU with a 6-h time resolution. We developed a histogram-based inten…
Validation of the 3D AMR SIP-CESE Solar Wind Model for Four Carrington Rotations
Wu, S. T.; Feng, Xueshang; Xiang, Changqing +5 more
We carry out the adaptive mesh refinement (AMR) implementation of our solar-interplanetary space-time conservation element and solution element (CESE) magnetohydrodynamic model (SIP-CESE MHD model) using a six-component grid system (Feng, Zhou, and Wu, Astrophys. J.655, 1110, 2007; Feng et al., Astrophys. J.723, 300, 2010). By transforming the gov…
Nonlinear Force-Free Extrapolation of Emerging Flux with a Global Twist and Serpentine Fine Structures
van Driel-Gesztelyi, L.; Démoulin, P.; Baker, D. +5 more
We study the flux emergence process in NOAA active region 11024, between 29 June and 7 July 2009, by means of multi-wavelength observations and nonlinear force-free extrapolation. The main aim is to extend previous investigations by combining, as much as possible, high spatial resolution observations to test our present understanding of small-scal…
Magnetic Topology of Active Regions and Coronal Holes: Implications for Coronal Outflows and the Solar Wind
Mandrini, C. H.; van Driel-Gesztelyi, L.; Culhane, J. L. +8 more
During 2 - 18 January 2008 a pair of low-latitude opposite-polarity coronal holes (CHs) were observed on the Sun with two active regions (ARs) and the heliospheric plasma sheet located between them. We use the Hinode/EUV Imaging Spectrometer (EIS) to locate AR-related outflows and measure their velocities. Solar-Terrestrial Relations Observatory (…
3D Reconstruction of a Rotating Erupting Prominence
Török, T.; Thompson, W. T.; Kliem, B.
A bright prominence associated with a coronal mass ejection (CME) was seen erupting from the Sun on 9 April 2008. This prominence was tracked by both the Solar Terrestrial Relations Observatory (STEREO) EUVI and COR1 telescopes, and was seen to rotate about the line of sight as it erupted; therefore, the event has been nicknamed the "Cartwheel CME…
Predictions of Energy and Helicity in Four Major Eruptive Solar Flares
Qiu, Jiong; Longcope, Dana W.; Kazachenko, Maria D. +1 more
In order to better understand the solar genesis of interplanetary magnetic clouds (MCs), we model the magnetic and topological properties of four large eruptive solar flares and relate them to observations. We use the three-dimensional Minimum Current Corona model (Longcope, 1996, Solar Phys.169, 91) and observations of pre-flare photospheric magn…