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Lorentz Force: A Possible Driving Force for Sunspot Rotation
Zhang, Hongqi; Liu, Yu; Li, Hui +5 more
Zhao and Kosovichev (Astrophys. J.591, 446, 2003) found two opposite sub-photospheric vortical flows in the depth range of 0 - 12 Mm around a fast rotating sunspot. So far there is no theoretical model explaining such flow motions. In this paper, we try to explain this phenomenon from the point of view of magnetic flux tubes interacting with large…
The Mechanisms of Particle Kinetics and Dynamics Leading to Seismic Emission and Sunquakes
Zharkova, V. V.
In this paper the mechanisms responsible for observational features associated with sunquakes induced by different classes of solar flares are compared. The role of high-energy particle beams via Coulomb and Ohmic heating of the ambient plasma and nonthermal excitation and ionization is explored for different beam parameters at various atmospheric…
A Comparison of Feature Classification Methods for Modeling Solar Irradiance Variation
Harvey, K. L.; Pap, J. M.; Jones, H. P. +4 more
Physical understanding of total and spectral solar irradiance variation depends upon establishing a connection between the temporal variability of spatially resolved solar structures and spacecraft observations of irradiance. One difficulty in comparing models derived from different data sets is that the many ways for identifying solar features su…
Radio Bursts Associated with Flare and Ejecta in the 13 July 2004 Event
Sakurai, T.; Pohjolainen, S.; Hori, K.
We investigate coronal transients associated with a GOES M6.7 class flare and a coronal mass ejection (CME) on 13 July 2004. During the rising phase of the flare, a filament eruption, loop expansion, a Moreton wave, and an ejecta were observed. An EIT wave was detected later on. The main features in the radio dynamic spectrum were a frequency-drif…
A Study of Solar Radio Bursts with Fine Structures during Flare/CME Events
Huang, J.; Yan, Y. H.; Liu, Y. Y.
We have selected 27 solar microwave burst events recorded by the Solar Broadband Radio Spectrometer (SBRS) of China, which were accompanied by M/X class flares and fast CMEs. A total of 70.4% of radio burst events peak at 2.84 GHz before the peaks of the related flares' soft X-ray flux with an average time difference of about 6.7 minutes. Almost a…
Unusual Zebra Patterns in the Decimeter Wave Band
Tan, Chengming; Yan, Yihua; Chernov, G. P. +2 more
An analysis of new observations showing fine structures consisting of narrowband fiber bursts as substructures of large-scale zebra-pattern stripes is carried out. We study four events using spectral observations taken with a newly built spectrometer located at the Huairou station, China, in the frequency range of 1.1 - 2.0 GHz with extremely high…
Automatic Recognition and Characterisation of Supergranular Cells from Photospheric Velocity Fields
Potts, H. E.; Diver, D. A.
We have developed an exceptionally noise-resistant method for accurate and automatic identification of supergranular cell boundaries from velocity measurements. Because of its high noise tolerance the algorithm can produce reliable cell patterns with only very small amounts of smoothing of the source data in comparison to conventional methods. In …
Space Weather Application Using Projected Velocity Asymmetry of Halo CMEs
Gopalswamy, N.; Michalek, G.; Yashiro, S.
Halo coronal mass ejections (HCMEs) originating from regions close to the center of the Sun are likely to be responsible for severe geomagnetic storms. It is important to predict geoeffectiveness of HCMEs by using observations when they are still near the Sun. Unfortunately, coronagraphic observations do not provide true speeds of CMEs because of …
The Observed Long- and Short-Term Phase Relation between the Toroidal and Poloidal Magnetic Fields in Cycle 23
Zharkova, V.; Zharkov, S.; Gavryuseva, E.
The observed phase relations between the weak background solar magnetic (poloidal) field and strong magnetic field associated with sunspots (toroidal field) measured at different latitudes are presented. For measurements of the solar magnetic field (SMF) the low-resolution images obtained from Wilcox Solar Observatory are used and the sunspot magn…
On 17 22 January 2005 Events in Space Weather
Kudela, K.; Rybanský, M.; Dorotovič, I. +1 more
This contribution is a follow-up to the recent paper of Kuznetsov et al. (Contrib. Astron. Obs. Skalnaté Pleso36, 85, 2006) on the ground level enhancement (GLE) on 20 January 2005. We focused on a study of Forbush decrease (FD) of 17 - 18 and 21 - 22 January 2005, respectively. The data from the neutron monitor at Lomnický Štít (1 min counts) and…