An ionization-diffusion mechanism is proposed to understand the first ionization potential (FIP) fractionation as observed in the solar corona and the solar wind. The enrichment of the low-FIP elements (<10 eV) compared to the highFIP elements in a large variety of phenomena, as e.g. slow and fast wind or polar plumes, is explained. Also the special behaviour of the heavy noble gases becomes pe...

This work devotes to investigations of solar corona and solar wind plasma by the method of radio probing with using of very long baseline interferometry (VLBI). We performed the theoretical calculation of power spectrum of interferometric response to radio source emission, passed through the turbulent medium. Data of theoretical analysis are compared with results of international VLBI experimen...

The acceleration of the low-latitude solar wind, which comes from regions of the corona above large, closed magnetic loops, is a theoretical challenge. Until recently we have lacked direct measurements close to the Sun with which to constrain the theory. When a series of high-resolution coronagraph images is viewed in the form of a movie the continuous outflow of matter from the Sun is very obv...

Solar energetic particles (SEPs), like the solar wind, provide a direct sample of the Sun. Although SEP abundances show a variable amount of mass fractionation, it is possible to develop methods of correcting for it in order to deduce the composition of the corona. Using high-resolution measurements from the Solar Isotope Spectrometer on the Advanced Composition Explorer, we have studied the is...

The SOHO Ultraviolet Coronagraph Spectrometer (UVCS/SOHO) has observed the extended solar corona between 1 and 10 R for more than two years. We review spectroscopic and polarimetric measurements made in coronal holes, equatorial streamers, and coronal mass ejections, as well as selected non-solar targets. UVCS/SOHO has provided a great amount of empirical information about the physical processe...

[1] The primary goal of this paper is to provide estimates of upstream solar wind plasma conditions at Mercury during the January 2008 MESSENGER flyby, based on two completely independent solar wind models. The first is a steady-state three-dimensional (3-D) magnetohydrodynamic (MHD) model of the solar corona and inner heliosphere, which simulates the solar wind propagation from the source surf...

Throughout its high-latitude excursion Ulysses has observed several types of solar wind structures. In addition to structures such as Alfven waves, compressional features, and microstreams, the solar wind also contains low contrast pressure-balance structures (PBSs). The PBSs are marked by an anti-correlation of the plasma and field pressures; their signatures are often hidden by the comparativ...

We investigate the formation of steady gas flows—so-called electric winds—created by point-plane corona discharges driven by time oscillating (ac) electric fields. By varying the magnitude and frequency of the applied field, we identify two distinct scaling regimes: (i) a low frequency (dc) regime and (ii) a high frequency (ac) regime. These experimental observations are reproduced and explaine...

Ionic wind devices or electrostatic fluid accelerators are becoming of increasing interest as tools for thermal management, in particular for semiconductor devices. In this work, we present a numerical model for predicting the performance of such devices, whose main benefit is the ability to accurately predict the amount of charge injected at the corona electrode. Our multiphysics numerical mod...

Using polarized brightness (pB) measurements made by the High Altitude Observatory (HAO) Mauna Loa Mk III K-coronameter, we investigate the daily changes of path-integrated density at 1.15 R,. During 1996, when simultaneous pB and helioseismology data were available, we find that the correlation of pB (at zero time lag and 207 latitude lag) varies with latitude in the same way that the subsurfa...