Search Publications
A Comparison of Flare Forecasting Methods. I. Results from the “All-Clear” Workshop
Schrijver, C. J.; Zhang, J.; Leka, K. D. +15 more
Solar flares produce radiation that can have an almost immediate effect on the near-Earth environment, making it crucial to forecast flares in order to mitigate their negative effects. The number of published approaches to flare forecasting using photospheric magnetic field observations has proliferated, with varying claims about how well each wor…
Predicting Coronal Mass Ejections Using Machine Learning Methods
Ilonidis, S.; Bobra, M. G.
Of all the activity observed on the Sun, two of the most energetic events are flares and coronal mass ejections (CMEs). Usually, solar active regions that produce large flares will also produce a CME, but this is not always true. Despite advances in numerical modeling, it is still unclear which circumstances will produce a CME. Therefore, it is wo…
Small-scale Magnetic Islands in the Solar Wind and Their Role in Particle Acceleration. II. Particle Energization inside Magnetically Confined Cavities
Zank, Gary P.; Li, Gang; Malandraki, Olga E. +3 more
We explore the role of heliospheric magnetic field configurations and conditions that favor the generation and confinement of small-scale magnetic islands associated with atypical energetic particle events (AEPEs) in the solar wind. Some AEPEs do not align with standard particle acceleration mechanisms, such as flare-related or simple diffusive sh…
FRiED: A Novel Three-dimensional Model of Coronal Mass Ejections
Isavnin, A.
We present a novel three-dimensional (3D) model of coronal mass ejections (CMEs) that unifies all key evolutionary aspects of CMEs and encapsulates their 3D magnetic field configuration. This fully analytic model is capable of reproducing the global geometrical shape of a CME with all major deformations taken into account, I.e., deflection, rotati…
Longitudinal Properties of a Widespread Solar Energetic Particle Event on 2014 February 25: Evolution of the Associated CME Shock
Lario, D.; Anderson, B. J.; Kwon, R. -Y. +8 more
We investigate the solar phenomena associated with the origin of the solar energetic particle (SEP) event observed on 2014 February 25 by a number of spacecraft distributed in the inner heliosphere over a broad range of heliolongitudes. These include spacecraft located near Earth; the twin Solar TErrestrial RElations Observatory spacecraft, STEREO…
Solar Cycle 25: Another Moderate Cycle?
Schüssler, M.; Jiang, J.; Cameron, R. H.
Surface flux transport simulations for the descending phase of Cycle 24 using random sources (emerging bipolar magnetic regions) with empirically determined scatter of their properties provide a prediction of the axial dipole moment during the upcoming activity minimum together with a realistic uncertainty range. The expectation value for the dipo…
The Major Geoeffective Solar Eruptions of 2012 March 7: Comprehensive Sun-to-Earth Analysis
Gontikakis, C.; Patsourakos, S.; Tsinganos, K. +33 more
During the interval 2012 March 7-11 the geospace experienced a barrage of intense space weather phenomena including the second largest geomagnetic storm of solar cycle 24 so far. Significant ultra-low-frequency wave enhancements and relativistic-electron dropouts in the radiation belts, as well as strong energetic-electron injection events in the …
Relationship of EUV Irradiance Coronal Dimming Slope and Depth to Coronal Mass Ejection Speed and Mass
Vourlidas, Angelos; Colaninno, Robin C.; Woods, Thomas N. +3 more
Extreme ultraviolet (EUV) coronal dimmings are often observed in response to solar eruptive events. These phenomena can be generated via several different physical processes. For space weather, the most important of these is the temporary void left behind by a coronal mass ejection (CME). Massive, fast CMEs tend to leave behind a darker void that …
The 2012 July 23 Backside Eruption: An Extreme Energetic Particle Event?
Gopalswamy, N.; Yashiro, S.; Mäkelä, P. +3 more
The backside coronal mass ejection (CME) of 2012 July 23 had a short Sun-to-Earth shock transit time (18.5 hr). The associated solar energetic particle (SEP) event had a >10 MeV proton flux peaking at ∼5000 pfu, and the energetic storm particle event was an order of magnitude larger, making it the most intense event in the space era at these en…
Why is a Flare-rich Active Region CME-poor?
Wang, Yuming; Shen, Chenglong; Wang, Jingxiu +6 more
Solar active regions (ARs) are the major sources of two of the most violent solar eruptions, namely flares and coronal mass ejections (CMEs). The largest AR in the past 24 years, NOAA AR 12192, which crossed the visible disk from 2014 October 17 to 30, unusually produced more than one hundred flares, including 32 M-class and 6 X-class ones, but on…