نتایج جستجو برای: sun corona
تعداد نتایج: 47564 فیلتر نتایج به سال:
A new interaction is derived, which is important only when photons penetrate a hot, sparse electron plasma. When photons penetrate a cold and dense electron plasma, they lose energy through ionization and excitation, through Compton scattering on the individual electrons, and through Raman scattering on the plasma frequency. But when the plasma is very hot and has low density, such as in the so...
Estimating the structure, or density distribution, of the solar corona from a set of 2D white light images made by coronagraphs is a critical challenge in coronal physics. This work describes new data analysis procedures which are used to create global maps of the coronal structure at heights where the corona becomes approximately radial (≥3R ). The technique, which is named Qualitative Solar R...
[1] Results from the first Sun-to-Earth coupled numerical model developed at the Center for Integrated Space Weather Modeling are presented. The model simulates physical processes occurring in space spanning from the corona of the Sun to the Earth’s ionosphere, and it represents the first step toward creating a physics-based numerical tool for predicting space weather conditions in the near-Ear...
Sensitive radio observations of the 1997 September 24 EIT wave show its velocity to be 830 km s−1. The wave first appears a short distance from the flare site, and its trajectory projects back to the flare site at the peak of the impulsive phase. The radio spectrum appears to be consistent with optically thin coronal emission rather than chromospheric emission. The observed radio brightness tem...
By explicitly taking into account effects of Alfvén waves, I derive from a simple energetics argument a fundamental relation which predicts solar wind (SW) speeds in the vicinity of the earth from physical properties on the sun. Kojima et al. recently found from their observations that a ratio of surface magnetic field strength to an expansion factor of open magnetic flux tubes is a good indica...
We present results from the the first campaign of dedicated solar observations undertaken by the Nuclear Spectroscopic Telescope ARray (NuSTAR) hard X-ray telescope. Designed as an astrophysics mission, NuSTAR nonetheless has the capability of directly imaging the Sun at hard X-ray energies (>3 keV) with an increase in sensitivity of at least two magnitude compared to current non-focusing teles...
Solar coronal mass ejections (CMEs) are associated with many dynamical phenomena, among which EIT waves have always been a puzzle. In this Letter MHD processes of CME-induced wave phenomena are numerically simulated. It is shown that as the flux rope rises, a piston-driven shock is formed along the envelope of the expanding CME, which sweeps the solar surface as it propagates. We propose that t...
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