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Comparison of energies between eruptive phenomena and magnetic field in AR 10930

Ravindra, B.; Howard, Timothy A.

We present a study comparing the energy carried away by a coronal mass ejection (CME) and the radiative energy loss in associated flare plasma, with the decrease in magnetic free energy during a release in active region NOAA 10930 on December 13, 2006 during the declining phase of the solar cycle 23. The ejected CME was fast and directed towards t…

Excitation of Solar p-mode Oscillations by Flares

Basu, Sarbani; Antia, H. M.; Ambastha, Ashok

Solar flares release large amounts of energy at different layers of the solar atmosphere. It is, therefore, expected that major flares would be able to excite waves, thereby affecting the p-mode oscillation characteristics. From the analysis of MDI data, we find that power in p-modes appears to increase for some flares, beyond the normal values ex…

On the Rapid Variations of Solar Magnetic Fields

Venkatakrishnan, P.; Kumar, Brajesh; Ravindra, B.

We report on the rapid variations of solar magnetic fields that appear to be enhanced significantly above the background variability, at a few locations within the solar active regions, as observed with the Michelson Doppler Imager (MDI) on board the SOHO spacecraft. The pressure fluctuations estimated to arise from this variability far exceed the…

Solar Cycle Variation in GONG and MDI Data : 1995-2002

Tripathy, S. C.

Both GONG and MDI projects have measured p-mode frequencies of the Sun for more than 7 years. Here we review what we have learnt from the temporal variation of the oscillation frequencie and splitting coefficients.

Geomagnetic storms with H 400nT during 1979-99

Kumar, Santosh; Pratap Yadav, Mahendra

The effect of solar features on geospheric conditions leading to ninety nine geomagnetic storms (GMSs) with H400nT and Ap20 have been investigated using interplanetary magnetic field (IMF), solar wind plasma (SWP) and solar geophysical data (SGD) during the period 1979-99. H, X-ray solar o o flares occured within lower latitudinal zone i.e., 30 N-…

Solar rotation rate from minimum to maximum of activity cycle

Kumar, Brajesh; Tripathy, S. C.; Jain, Kiran +1 more

Using helioseismic data from SOI/MDI and GONG for the current solar cycle 23, from solar minimum to near maximum phase, we report here on the temporal variation of the rotation rate.

Sumer/soho

Dwivedi, B. N.

Plasma diagnostics for SUMER on board the SOHO mission

Dwivedi, B. N.