Search Publications
How Many CMEs Have Flux Ropes? Deciphering the Signatures of Shocks, Flux Ropes, and Prominences in Coronagraph Observations of CMEs
Li, Y.; Lynch, B. J.; Howard, R. A. +1 more
We intend to provide a comprehensive answer to the question on whether all Coronal Mass Ejections (CMEs) have flux rope structure. To achieve this, we present a synthesis of the LASCO CME observations over the last 16 years, assisted by 3D MHD simulations of the breakout model, EUV and coronagraphic observations from STEREO and SDO, and statistics…
Propagation of Interplanetary Coronal Mass Ejections: The Drag-Based Model
Möstl, C.; Temmer, M.; Rollett, T. +9 more
We present the "Drag-Based Model" (DBM) of heliospheric propagation of interplanetary coronal mass ejections (ICMEs). The DBM is based on the hypothesis that the driving Lorentz force, which launches a CME, ceases in the upper corona and that beyond a certain distance the dynamics becomes governed solely by the interaction of the ICME and the ambi…
Detection of Equatorward Meridional Flow and Evidence of Double-cell Meridional Circulation inside the Sun
Kosovichev, A. G.; Zhao, Junwei; Duvall, T. L., Jr. +2 more
Meridional flow in the solar interior plays an important role in redistributing angular momentum and transporting magnetic flux inside the Sun. Although it has long been recognized that the meridional flow is predominantly poleward at the Sun's surface and in its shallow interior, the location of the equatorward return flow and the meridional flow…
Direct Evidence for a Fast Coronal Mass Ejection Driven by the Prior Formation and Subsequent Destabilization of a Magnetic Flux Rope
Patsourakos, S.; Stenborg, G.; Vourlidas, A.
Magnetic flux ropes play a central role in the physics of coronal mass ejections (CMEs). Although a flux-rope topology is inferred for the majority of coronagraphic observations of CMEs, a heated debate rages on whether the flux ropes pre-exist or whether they are formed on-the-fly during the eruption. Here, we present a detailed analysis of extre…
A major solar eruptive event in July 2012: Defining extreme space weather scenarios
Galvin, A. B.; Baker, D. N.; Li, X. +4 more
key goal for space weather studies is to define severe and extreme conditions that might plausibly afflict human technology. On 23 July 2012, solar active region 1520 (~141°W heliographic longitude) gave rise to a powerful coronal mass ejection (CME) with an initial speed that was determined to be 2500 ± 500 km/s. The eruption was directed away fr…
Longitudinal and Radial Dependence of Solar Energetic Particle Peak Intensities: STEREO, ACE, SOHO, GOES, and MESSENGER Observations
Lario, D.; Roelof, E. C.; Ho, G. C. +5 more
Simultaneous measurements of solar energetic particle (SEP) events by two or more of the spacecraft located near 1 AU during the rising phase of solar cycle 24 (i.e., STEREO-A, STEREO-B, and near-Earth spacecraft such as ACE, SOHO, and GOES) are used to determine the longitudinal dependence of 71-112 keV electron, 0.7-3 MeV electron, 15-40 MeV pro…
Implications of Mass and Energy Loss due to Coronal Mass Ejections on Magnetically Active Stars
Drake, Jeremy J.; Gopalswamy, Nat; Yashiro, Seiji +1 more
Analysis of a database of solar coronal mass ejections (CMEs) and associated flares over the period 1996-2007 finds well-behaved power-law relationships between the 1-8 Å flare X-ray fluence and CME mass and kinetic energy. We extrapolate these relationships to lower and higher flare energies to estimate the mass and energy loss due to CMEs from s…
The Driver of Coronal Mass Ejections in the Low Corona: A Flux Rope
Liu, Y.; Cheng, X.; Ding, M. D. +2 more
Recent Solar Dynamic Observatory observations reveal that coronal mass ejections (CMEs) consist of a multi-temperature structure: a hot flux rope and a cool leading front (LF). The flux rope first appears as a twisted hot channel in the Atmospheric Imaging Assembly (AIA) 94 Å and 131 Å passbands. The twisted hot channel initially lies along the po…
Solar Flare Prediction Using Advanced Feature Extraction, Machine Learning, and Feature Selection
Gallagher, Peter T.; Bloomfield, D. Shaun; Colak, Tufan +3 more
Novel machine-learning and feature-selection algorithms have been developed to study: i) the flare-prediction-capability of magnetic feature (MF) properties generated by the recently developed Solar Monitor Active Region Tracker (SMART); ii) SMART's MF properties that are most significantly related to flare occurrence. Spatiotemporal association a…
Comparison of Kepler Photometric Variability with the Sun on Different Timescales
Basri, Gibor; Walkowicz, Lucianne M.; Reiners, Ansgar
We utilize Kepler data to study the precision differential photometric variability of solar-type and cooler stars at different timescales, ranging from half an hour to three months. We define a diagnostic that characterizes the median differential intensity change between data bins of a given timescale. We apply the same diagnostics to Solar and H…