Search Publications
Solar eruptions and long wavelength radio bursts: The 1997 May 12 event
Kaiser, M. L.; Gopalswamy, N.
We report on the cause of the 1997 May 12 type II bursts observed by ground based and space-based radio instruments. We estimate the fast mode speed in the corona as a function of heliocentric distance to identify the regions where fast mode shocks can be driven by CMEs. We find that both the coronal and the interplanetary type II bursts can be ex…
Laboratory calibration of the cassini cosmic dust analyser (CDA) using new, low density projectiles
Srama, R.; Grün, E.; Müller, M. +9 more
The Cassini Cosmic Dust Analyser (CDA), developed from the Galileo and Ulysses dust instruments with the addition of a Chemical Analyser, is currently travelling outward from the Earth (collecting data from March 1999 onward) to the Saturnian system (arrival 2004) via Jupiter. The Chemical Analyser will provide information on the elemental composi…
Modeling the radial variation of coronal streamer belts during sunspot ascending phase
Hoeksema, J. T.; Zhao, X. P.; Rich, N. B.
The coronal streamer belts and their radial variation between 2.5 and 20.0 solar radii in the ascending phase of the solar cycle can be well reproduced using the horizontal current-current sheet-source surface magnetic field model with the set of model parameters determined based on MDI and LASCO Carrington maps during 1996 minimum activity phase.
Total solar irradiance variations since 1978
Fröhlich, Claus
A composite record of solar total irradiance compiled from measurements made by five independent space-based radiometers since 1978 is the basis for an evaluation of the influence of solar activity on total solar irradiance. An empirical model that parameterizes the combined influences of dark sunspots and bright faculae features on solar irradian…
Relationships between CME's and prominences
van Driel-Gesztelyi, L.; Aulanier, G.; Schmieder, B. +6 more
We have studied the erupting prominences which were associated with coronal mass ejections during a series of campaigns involving both spacecraft and ground-based observatories. The evolution of the physical conditions within the prominences was established from Hα and magnetic field observations. Particular attention ahs been paid to the presence…
New insights on the onsets of coronal mass ejections from soho
St. Cyr, O. C.; Plunkett, S. P.; Michels, D. J. +6 more
Coronal mass ejections (CMES) are among the most dramatic forms of transient activity occurring in the solar atmosphere. Despite over twenty years of research, many basic questions related to the physics of CMEs have remained unanswered. Observations with the LASCO and EIT experiments on SOHO, combined with recent theoretical modeling, have provid…
The composition of the solar wind
Wimmer-Schweingruber, Robert F.
Accurate knowledge of the composition of the solar wind and of solar system abundances allows us to improve our understanding about various processes affecting the elemental, isotopic, and charge-state abundances of the solar wind. During the evolution of the Sun, isotopic and elemental abundances have been affected by migration processes at the i…
Solar cycle variation of the radiance and the global electron density of the solar corona
Llebaria, A.; Quemerais, E.; Lamy, P.
The question of the global activity of the solar corona, as a function of time and distance from the center of the Sun, is considered by analyzing SOHO/LASCO-C2 daily polarized images over four years, i.e., from the minimum to the rising phase of the 23rd solar cycle. After proper correction for instrumental polarization, they are combined to prod…
The SOHO CELIAS/SEM EUV database from SC23 minimum to the present
Judge, D. L.; Ogawa, H. S.; Pap, J. M. +2 more
The SOHO Solar EUV Monitor has been in operation since December 1995 onboard the SOHO spacecraft. This instrument is a highly stable transmission grating solar extreme ultraviolet spectrometer. It has made nearly continuous full disk solar irradiance measurements both within an 8 nm bandpass centered at 30.4 nm and throughout the 0.1 to 50 nm sola…
How much of the solar irradiance variations is caused by the magnetic field at the solar surface?
Solanki, S. K.; Fligge, M.
The contribution to total solar irradiance variations by the magnetic field at the solar surface is estimated. Detailed models of the irradiance changes on the basis of magnetograms show that magnetic features at the solar surface account for over 90% of the irradiance variations on a solar rotation time scale and at least 70% on a solar cycle tim…