Search Publications
An XMM-Newton observation of the flare star AU MIC
Mewe, R.; Audard, M.; Güdel, M. +1 more
Preliminary results from an XMM- Newton observation of the active flare star AU Mic are presented. During the observation six flares were observed, along with numerous smaller-scale events. Coronal densities have been obtained using the density-sensitive He-like line triplet of O VII, for both the full observation and the final four flares. High b…
Wind-Ulysses in-situ thermal noise measurements of solar wind electron density and core temperature at solar maximum and minimum
Maksimovic, M.; Issautier, K.; Hoang, S. +2 more
The radio receivers on the Wind and Ulysses spacecraft in the solar wind continuously record spectra of the quasi-thermal plasma noise near the electron plasma frequency, from which the electron density and core temperature can be determined using the method of quasi-thermal noise spectroscopy. Such in-situ thermal noise measurements were obtained…
Coronal mass ejection interaction and particle acceleration during the 2001 April 14 15 events
Kaiser, M. L.; Howard, R. A.; Gopalswamy, N. +1 more
Two successive solar energetic particle (SEP) events associated with fast and wide coronal mass ejections (CMEs) on 2001 April 14 and 15 are compared. The weak SEP event of April 14 associated with an 830 km/s CME and an M1.0 flare was the largest impulsive event of cycle 23. The April 15 event, the largest ground level event of cycle 23, was thre…
First results of a new 3-D model of the time-dependent modulation of electrons in the heliosphere
Fichtner, H.; Ferreira, S. E. S.; Potgieter, M. S. +2 more
We employ our recently developed ansatz for the time-dependent 3-D modelling of Jovian and galactic electrons in the inner heliosphere. The main goal of the study is to check whether the form of the diffusion tensofi as determined recently by Ferreira et al. (2001a,b) with an extended parameter study of the steady state is also useful for comparis…
Search for a chromospheric resonator above sunspots
Kjeldseth-Moe, O.; Brekke, P.; Brynildsen, N. +2 more
We have recently observed thirteen sunspots, both with CDS on SOHO and TRACE. For each sunspot we investigate the oscillations in the chromosphere, transition region and corona. Above the umbra the power spectra show one dominant peak corresponding to a period of 3 minutes. The intensity oscillation amplitude increases with increasing temperature,…
Flare characteristics: Properties of eruptive and non-eruptive events and their associations
Culhane, J. L.; Harra, L. K.; Kay, H. R. M. +1 more
The complex: relationship between solar flares and coronal mass ejections is investigated using a comparison of flare parameters for a total of 69 ejective and non-ejective flares. In the case of solar flares which do not show mass ejection there seems to be a clear relationship between the peak intensity and duration, with higher intensity events…
On the sudden disappearances of solar filaments and their relationship with coronal mass ejections
Pojoga, S.; Huang, T. S.
Sudden disappearances of prominences/filaments were identified from the Prairie View Solar Observatory H α imagesand Meudon Observatory spectroheliograms for the period January 1, 2000 to March 31, 2000. Three classes of disappearances were considered for the purpose of this study: eruptive, quasi-eruptive and vanishing filaments. The H α events w…
Advances in magnetospheric radio wave analysis and tomography
Gurnett, D. A.; Escoubet, C. P.; Pickett, J. S. +7 more
Initial theoretical studies of multi-spacecraft radio tomographic imaging of the magnetosphere have shown the potential scientific value of the technique. We report a series of multistatic radio propagation experiments with the goal of testing and verifying the capabilities of radio tomography. These experiments focused specifically on measuring t…
Modeling solar and stellar flares
Reale, F.
The thermal phase of solar X-ray flares has been described as heating-triggered evolution of plasma confined in coronal loops. This paper describes how the modeling of the thermal phase of spatially resolved solar X-ray flares has been extended to investigate spatially unresolved stellar X-ray flares with different scopes, aims and perspectives. H…
Transport of a few-MEV jovian and galactic electrons at solar maximum
Ferreira, S. E. S.; Potgieter, M. S.; Heber, B. +2 more
The heliospheric modulation of galactic and jovian electrons is studied using a three-dimensional, steady-state model based on Parker's transport equation including the jovian source. The model is developed to study both jovian and galactic electrons. It is illustrated how the electron intensity-time profile along the Ulysses trajectory is effecte…