Search Publications
Driving major solar flares and eruptions: A review
Schrijver, Carolus J.
This review focuses on the processes that energize and trigger M- and X-class solar flares and associated flux-rope destabilizations. Numerical modeling of specific solar regions is hampered by uncertain coronal-field reconstructions and by poorly understood magnetic reconnection; these limitations result in uncertain estimates of field topology, …
Modelling and observations of photospheric magnetic helicity
Démoulin, P.; Pariat, E.
Mounting observational evidence of the emergence of twisted magnetic flux tubes through the photosphere have now been published. Such flux tubes, formed by the solar dynamo and transported through the convection zone, eventually reach the solar atmosphere. Their accumulation in the solar corona leads to flares and coronal mass ejections. Since rec…
Solar irradiance forecast and far-side imaging
Haberreiter, M.; Fontenla, J. M.; Lindsey, C. +2 more
This paper presents a new approach to forecasting short-term Lyα solar irradiance variations due to the presence and evolution of magnetically heated regions in the Sun's outer atmosphere. This scheme is based on images of the solar disk at key wavelengths, currently Ca II K filtergrams, maps of backscattered solar Lyα from the interplanetary medi…
Analyses of magnetic field structures for active region 10720 using a data-driven 3D MHD model
Liu, Yang; Wu, S. T.; Yurchyshyn, Vasyl +5 more
In order to understand solar eruptive events (flares and CMEs) we need to investigate the changes at the solar surface. Thus, we use a data-driven, three-dimensional magnetohydrodynamic (MHD) model to analyze a flare and coronal mass ejection productive active region, AR 10720 on January 15, 2005. The measured magnetic field from Big Bear Solar Ob…
CME-flare association during the 23rd solar cycle
Beheary, M. M.; Youssef, M.; Mawad, R. +2 more
The relation between coronal mass ejections (CMEs) and solar flares are statistically studied. More than 10,000 CME events observed by SOHO/LASCO during the period 1996-2005 have been analyzed. The soft X-ray flux measurements provided by the Geostationary Operational Environmental Satellite (GOES), recorded more than 20,000 flares in the same tim…
Solar and interplanetary origins of the November 2004 superstorms
Tsurutani, Bruce T.; Echer, Ezequiel; Guarnieri, Fernando L.
During the first half of November 2004, many solar flares and coronal mass ejections (CMEs) were associated with solar active region (AR) 10696. This paper attempts to identify the solar and interplanetary origins of two superstorms which occurred on 8 and 10 November with peak intensities of Dst = -373 nT and -289 nT, respectively. Southward inte…
Solar proton enhancements in different energy channels and coronal mass ejections during the last solar cycle
Mavromichalaki, H.; Belov, A.; Gerontidou, M. +1 more
The main properties of 11622 coronal mass ejections (CMEs) observed by the Solar and Heliospheric Observatory (SOHO) mission’s Large Angle and Spectrometric Coronagraph (LASCO-C2) from January 1996 through December 2006 are considered. Moreover, the extended database of solar proton enhancements (SPEs) with proton flux >0.1 pfu at energy >10…
Interpretation of the SOHO/UVCS observations of two CME-driven shocks
Mancuso, Salvatore; Bemporad, Alessandro
We report on the analysis of two fast CME-driven shocks observed with the UltraViolet Coronagraph Spectrometer (UVCS) on board the Solar and Heliospheric Observatory (SOHO). The first event, detected on 2002 March 22 at 4.1 R⊙ with the UVCS slit placed in correspondence with the flank of the expanding CME surface, represents the highest…
Experimental data and analysis of the October 2003 Forbush decrease
D'Andrea, C.; Poirier, J.; Balsara, D. S.
On October 28, 2003 an Earthward-directed coronal mass ejection (CME) was observed from SOHO/LASCO imagery in conjunction with an X17 solar flare. The CME, traveling at nearly 2000 km/s, impacted the Earth on October 29, 2003 causing ground-based particle detectors to register a counting rate drop known as a Forbush decrease. The CME was not only …
Asymmetric precipitation in a coronal loop as explanation of a singular observed spectrum
Mandrini, C. H.; Giménez de Castro, C. G.; Cristiani, G. +2 more
Almost 10 years of solar submillimeter observations have shown new aspects of solar activity, such as the presence of rapid solar spikes associated with the launch of coronal mass ejections and an increasing submillimeter spectral component in flares. We analyse the singular microwave-submillimeter spectrum of an M class solar flare on 20 December…