Search Publications
Energetic Electrons in Loop Top and Footpoint Microwave Sources
Zhou, A. H.; Su, Y. N.; Huang, G. L.
We have studied two microwave events with one-loop top (LT) and two-footpoint (FP) sources observed at 17 and 34 GHz by the Nobeyama Radioheliograph (NoRH). The microwave brightness peak is located near the FPs of the flare loop for one event, but near the LT for the other event. The microwave spectra of the FP sources are considerably softer (by …
A Flare and Umbral Flashes in a Sunspot
Turova, I. P.; Ozhogina, O. A.; Yurysheva, O. V.
We studied the evolution and dynamic processes in the chromosphere above a sunspot umbra. A relatively rarely occurring phenomenon of bright long-lasting emission observed in the umbra of a unipolar sunspot of the AR 9570 group on August 11, 2001 was investigated. It was found that during the course of the observation, emission was spreading, grad…
Deflection of coronal mass ejection in the interplanetary medium
Wang, Yuming; Shen, Chenglong; Wang, S. +1 more
A solar coronal mass ejection (CME) is a large-scale eruption of plasma and magnetic fields from the Sun. It is believed to be the main source of strong interplanetary disturbances that may cause intense geomagnetic storms. However, not all front-side halo CMEs can encounter the Earth and produce geomagnetic storms. The longitude distribution of t…
Three-Dimensional Structure of the Active Region Photosphere as Revealed by High Angular Resolution
Lites, B. W.; Title, A. M.; Berger, T. E. +1 more
Blue continuum images of active regions at ∼ 60° from the center of the solar disk obtained with the new Swedish 1-m Solar Telescope reveal heretofore unreported structure of the magnetized solar atmosphere. Perhaps the most striking aspect of these images is that, at an angular resolution of 0.12″, they show clearly the three-dimensional structur…
CME-Flare Association Deduced from Catastrophic Model of CMEs
Lin, Jun
Based on our previous works regarding solar eruptions, we focus on the relationships among different eruptive phenomena, such as solar flares, eruptive prominences and coronal mass ejections (CMEs). The three processes show clear correlations under certain circumstances. The correlation between a CME and solar flare depends the energy that stored …
Organized Subsurface Flows near Active Regions
Thompson, M. J.; Toomre, J.; Hindman, B. W. +1 more
Local helioseismic techniques, such as ring analysis and time-distance helioseismology, have already shown that large-scale flows near the surface converge towards major active regions. Ring analysis has further demonstrated that at greater depths some active regions exhibit strong outflows. A critique leveled at the ring-analysis results is that …
Characteristics of active-region sources of solar wind near solar maximum
Neugebauer, M.; Liewer, Paulett C.; Zurbuchen, Thomas
Previous studies of the source regions of solar wind sampled by ACE and Ulysses showed that some solar wind originates from open magnetic flux rooted in active regions. These solar wind sources were labeled active-region sources when the open flux was from a strong field region with no corresponding coronal hole in the NSO He 10830 Å synoptic coro…
Coronal Shocks of November 1997 Revisited: The Cme Type II Timing Problem
Thompson, B. J.; Zhang, J.; Nitta, N. V. +1 more
We re-examine observations bearing on the origin of metric type II bursts for six impulsive solar events in November 1997. Previous analyses of these events indicated that the metric type IIs were due to flares (either blast waves or ejecta). Our point of departure was the study of Zhang et al. (2001) based on the Large Angle and Spectrometric Cor…
Measurement and Uncertainty of the Long-Term Total Solar Irradiance Trend
Mekaoui, Sabri; Dewitte, Steven; Crommelynck, Dominique +1 more
A possible long-term trend of the total solar irradiance could be a natural cause for climate variations on Earth. Measurement of the total solar irradiance with space radiometers started in 1978. We present a new total solar irradiance composite, with an uncertainty of ± 0.35 W m−2. From the minimum in 1995 to the maximum in 2002 the t…
Coronal Mass Ejection of 15 May 2001: II. Coupling of the Cme Acceleration and the Flare Energy Release
Maričić, D.; Vršnak, B.; Stanger, A. L. +1 more
We analyze the relationship between the dynamics of the coronal mass ejection (CME) of 15 May 2001 and the energy release in the associated flare. The flare took place behind the east limb and was disclosed by a growing system of hot soft X-ray (SXR) loops that appeared from behind the limb around the onset of the rapid acceleration of the CME. Th…