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The Quiet Sun Atmosphere as Seen by Soho
Keenan, F. P.; Phillips, K. J. H.; Gallagher, P. T. +2 more
The recent solar minimum has allowed studies to be made of quiet-Sun structures with SOHO instruments with better resolution than before. This paper reports on the morphology and dynamics of the EUV emission, including the chromospheric and transition-region network and coronal features, and how the photospheric magnetic field and coronal bright p…
Coronal Mass Ejections and Large Scale Structure of the Corona
Schwenn, R.; Pick, M.; Lamy, P. +3 more
A comparative study of two events accompanied by both a flare and a CME has been performed. The data analysis has been made by comparing the observations of the LASCO/SOHO coronagraphs with those of the Nancay radioheliograph. The observations show a clear connection between coronal green and red line transient activity, burst radio emission and t…
Cooling of Energetic Particles during their Transport along Spiral Field Lines
Kóta, J.
The transport of low-energy charged particles moving along magnetic field lines is considered. We point out that particles accelerated at CIRs at larger heliocentric distances and moving inward along the spiral field lose energy and decelerate even in a purely scatter free case. This results in a sizeable reduction in intensity. Scattering increas…
Dynamics of Chromiospheric and Transition Region Lines Observed with SOHO/SUMER and the GCT/Tenerife
Wilhelm, K.; Schühle, U.; Foing, B. H. +3 more
High-resolution spectroscopic observations of the quiet Sun have been carried out in September 1996 at the German Gregory Coudé Telescope (GCT) in Tenerife and in May 1997 with the SUMER instrument onboard SOHO. Time sequences of spectra in the visible and near infrared as well as in the ultraviolet have been taken, covering a range of heights fro…
Coupling Between High and Low Latitudes as Observed with Lasco in the Solar Corona and in Interplanetary Space
Schwenn, R.
From Skylab, Helios and Ulysses observations we had learnt already how closely the 3D heliosphere is related to the underlying coronal structure. Around solar activity minimum, large polar coronal holes dominate the major part of the heliosphere, through the high-speed solar wind streams emanating from them. A different type of solar wind is restr…
Dynamics in Restructuring Active Regions Observed During Soho/Yohkoh/Gbo Campaigns
Mandrini, C. H.; Nitta, N.; Fletcher, L. +6 more
JOP17 and JOP 33 are SOHO Joint Observing Programs in collaboration with Yohkoh/SXT and ground based observatories (GBO's), dedicated to observe dynamical events through the atmosphere. During runs of these programs we observed in restructuring active regions (ARs), surges, subflares, bright knots, but not large flares and jets. From these observa…
Radial Distance Dependence of the Solar Wind Speed at High Latitudes Observed by Interplanetary Scintillation
Tokumaru, M.; Kojima, M.; Yokobe, A.
We have investigated the radial distance dependence of the solar wind speed during the years 1995 and 1996 using interplanetary scintillation (IPS) observations at the Solar-Terrestrial Environment Laboratory. We derived solar wind velocity distributions for regions inside and outside of 0.3 AU separately using a computerized tomography method to …
Initial Results from the XUV Doppler Telescope
Kano, R.; Kobayashi, K.; Tsuneta, S. +6 more
We developed a unique telescope to obtain simultaneous XUV images and the velocity maps by measuring the line-of-sight Doppler shifts of the Fe XIV 211A&ring line (T = 1.8 MK): the Solar XUV Doppler Telescope (hereafter XDT). The telescope was launched by the Institute of Space and Astronautical Science with the 22nd S520 rocket on January 31,…
Coupling of the high and low latitude heliosphere and its relation to the corona. Proceedings. D0.7 Symposium of COSPAR Scientific Commission D held during 32nd COSPAR Scientific Assembly, Nagoya (Japan), 12 - 19 Jul 1998.
Kunow, H.
The following topics were dealt with: solar wind acceleration, interplanetary scintillation measurements, solar wind structure, solar wind acceleration region, 3D MHD simulations of coronal mass ejections, interplanetary magnetic clouds, coronal streamers, plasma velocity in interplanetary magnetic structures, H cell measurements, polar plume and …
Deep Survey Sources, and Predictions for XMM and AXAF
Ptak, A.; Georgantopoulos, I.; Griffiths, R. E. +6 more
From the deep surveys performed with the ROSAT and ASCA X-ray observatories, we have now built up a plausible picture of the constitution of the X-ray background and the way in which AGNs (and starburst nuclei surrounding AGNs) account for it. But major problems remain: the best model that we have is one in which the XRB above 3 kev is accounted f…