Search Publications
Longitudinal Distribution of Solar Flares and Their Association with Coronal Mass Ejections and Forbush Decreases
Shrivastava, Pankaj K.; Jothe, Mukesh K.; Singh, Mahendra
Major Hα solar-flare events of high optical importance have been employed to study their heliographic distribution in longitude around the Sun for the period of 2001 to 2006. A statistical analysis was performed to obtain their relationship with halo/partial-halo CMEs and Forbush decreases (Fds) of cosmic-ray intensity. Our analysis indicates that…
Crossing Filaments
Srivastava, A. K.; Filippov, Boris
Solar filaments show the position of large-scale polarity-inversion lines and are used for the reconstruction of large-scale solar magnetic field structure on the basis of Hα synoptic charts for the periods that magnetographic measurements are not available. Sometimes crossing filaments are seen in Hα filtergrams. We analyze daily Hα filtergrams f…
The Connection of Solar Wind Parameters with Radio and UV Emission from Coronal Holes
Myagkova, I. N.; Prosovetsky, D. V.
This paper presents the results of a comparison between observations of coronal holes in UV (SOHO EIT) and radio emission (17, 5.7 GHz, 327 and 150.9 MHz, from NoRH, SSRT and Nançay radioheliographs), and solar wind parameters, from ACE spacecraft data over the period 12 March - 31 May 2007. The increase in the solar wind velocity up to ∼ 600 km s…
Tracking a Ulysses High-latitude ICME Event Back to Its Solar Origins
Dumitrache, C.; Popescu, N. A.; Oncica, A.
High-latitude interplanetary mass ejections (ICMEs) observed beyond 1 AU are not studied very often. They are useful for improving our understanding of the 3D heliosphere. As there are only few such events registered by the Ulysses spacecraft, the task of detecting their solar counterparts is a challenge, especially during high solar activity peri…
Corrections to the Magnitude of Cross-Correlation Functions for Dispersion of Solar Acoustic Waves
Zhao, Hui; Liang, Zhi-Chao; Chou, Dean-Yi +2 more
The cross-correlation function is a useful tool in helioseismology. The magnitude of the cross-correlation function has been used to represent the power of wave packets. Dispersion causes a decrease in amplitude and an increase in width of wave packets. This leads to a decrease in magnitude and an increase in width of cross-correlation functions. …
Solar Activity Cycle in Solar-wind Sources and Flows
Lotova, N. A.; Obridko, V. N.; Vladimirskii, K. V.
Experiments based on multi-source radio occultation measurements of the circumsolar plasma at R∼4.0−70RS were carried out during 1997 - 2008 to locate the inner boundary of the solar-wind transonic transition region, Rin. The data obtained were used to correlate the solar-wind stream structure and magnetic fields on the sourc…
`Active Longitudes' in the Heliomagnetic Reference Frame
Obridko, V. N.; Ivanov, E. V.; Chertoprud, V. E.
A new coordinate system - heliomagnetic reference frame - has been proposed in which the great circle passes through the solar pole and the north pole of the magnetic dipole is considered as the central meridian. It is shown that, in the new coordinate system, the active longitudes are defined much more clearly, are more stable in time, and are in…
Properties of Granules in Upflows and Downflows
Yang, Shuhong; Jin, Chunlan; Yu, Daren +2 more
Normal-mode observations of seven quiet regions, obtained by the Hinode spacecraft, are used to analyze the physical properties of granules with mean upward and downward Doppler velocity. We identify 75 146 granules from the observations with a granule-detection method. Then the granules are divided into two subsets: one with negative mean Doppler…
Differential Rotation of Strong Magnetic Flux During Solar Cycles 21 - 23
Feng, X. S.; Song, W. B.; Shen, F. +1 more
In the present investigation we measure the differential rotation of strong magnetic flux during solar cycles 21 - 23 with the method of wavelet transforms. We find that the cycle-averaged synodic rotation rate of strong magnetic flux can be written as ω=13.47−2.58sin 2θ or ω=13.45−2.06sin 2θ−1.37sin 4θ, where θ is…
Distributions of Energy and Mass of Coronal Mass Ejections
Li, K. J.; Xu, J. C.; Gao, P. X.
The present study investigates the energy and mass distributions of all (11 322) coronal mass ejections (CMEs), 1406 CMEs associated solely with flares (FL CMEs), and 325 CMEs associated solely with filament eruptions (FE CMEs), all of which were observed by the Large Angle and Spectrometric Coronagraph on board the Solar and Heliospheric Observat…