Search Publications
Simultaneous observations of radio wave frequency and intensity fluctuations for estimates of solar wind speed
Bird, M. K.; Efimov, A. I.; Chashei, I. V. +1 more
A new method is developed for solar wind speed measurements based on simultaneous observations of radio wave temporal intensity and frequency fluctuations. An estimate of the solar wind convection velocity is obtained from a combination of the frequency (Doppler) fluctuation spectral power at low fluctuating frequency and the power in the flat par…
The mean stellar parameters from IUE and hipparcos data
Niemczura, E.; Cugier, H.; Daszyńska, J.
Fine structure of the polar cusp as deduced from the plasma wave and plasma measurements
Sauvaud, J. -A.; Santolik, O.; Parrot, M. +7 more
Plasma waves are one of the most significant features of plasma. They are a very sensitive indicator of the boundaries and inner structure of different regions in space plasmas. The data gathered onboard Interball 1 and Magion 4 in the polar cusp indicate that plasma wave intensity changes very rapidly with a characteristic period of the order of …
Modulation effects of a changing solar wind speed on low-energy electrons
Ferreira, S. E. S.; Potgieter, M. S.; Moeketsi, D. M.
The heliospheric modulation of galactic and jovian electrons is studied using a fully three-dimensional, steady-state model based on Parker's transport equation including the jovian electron source. The model is used to study the transport of 7 MeV joviair and galactic electrons in the heliosphere by changing the solar wind speed profile from sola…
XMM- Newton observations of open clusters
Pallavicini, R.; Franciosini, E.; Randich, S.
We present observations of stellar clusters obtained with XMM- Newton as part of the Guaranteed Time program. We have obtained EPIC observations of the open clusters Praesepe, a Per, o Ori and Hyades and of the Taurus-Auriga star-forming region. The results of the analysis are presented and discussed, with emphasis on the imaging data. In all clus…
High-resolution XMM-Newton X-ray spectra of τ SCORPII
Raassen, A. J. J.; Mewe, R.; Güdel, M. +3 more
The first high-resolution X-ray spectra of the B0.2V star τ Scorpii obtained during 22.5ks on Aug. 20, 2001 with the RGS GRATING and the EPIC-MOS CCD spectrometers on board XMM-Newton exhibit bright emission lines of the H- and He-like ions of C, N, O, Ne, Mg, and Si, as well as Fe XVII and Fe XVIII lines. The emission line and continuum spectra h…
Shock acceleration of energetic particles in wave heated corona
Laitinen, T.; Vainio, R.
The solar wind wave heating models require substantial amount of wave power in order to efficiently heat and accelerate solar wind. The level of fluctuations is however limited by energetic particle observations. The simplest cyclotron sweep models result in convection-dominated transport, contradicting observations. However, models incorporating …
Solar radio emissions at solar maximum: Interplanetary perspective
Kaiser, M. L.
At frequencies below 10-15 MHz, radio astronomical observations of the sun are routinely performed in space because Earth's ionosphere effectively prohibits these low frequency emissions from reaching the ground. In terms of solar altitude, these frequencies correspond to about 2 Rs to 1 AU.At these low frequencies, a least four counterparts of th…
Use of non-radiation hardened micro-circuits in space — Experience from the cluster digital wave processor
Alleyne, H. St. C.; Yearby, K. H.
The trend for higher performance, lower cost, space instrumentation is leading towards the use commercial or industrial electronic parts, rather than specifically radiation hardened military grade parts. The micro-processor and memory devices used in the Cluster Digital Wave Processor (DWP) are not specifically radiation hardened parts, although t…
Chasing coronaij x-ray emission to the end of the pleiades main sequence … and beyond?
Briggs, K. R.; Pye, J. P.
We have used a 40-ks XMM-Newton observation to examine the X-ray emission of 33 proposed M-type members in. the core of the Pleiades. We reach a limiting X-ray luminosity of LX ≈ × 10 27 erg s -1 in the field centre and detect 17 of 19 members with MIc < 10.5 (where MIc