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A. Naam M.T. Meftah S. Douis S. Alexiou 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2014
In the present work we compute the real part of the impact collision operator for the electron broadening of ion lines in plasmas, taking into account relativistic effects in the dynamics of the perturbing electron. Specifically two relativistic effects are included: The modification of the trajectory due to non-Newtonian mechanics and the modification of the velocity distribution (Maxwell–Juttner). The results are compared to the non-relativistic case. 相似文献
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Amro F. Alasta Abdulrazag Algamudi Rami Qahwaji Stanley Ipson Alain Hauchecorne Mustapha Meftah 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2019,63(1):606-616
PICARD is a space-based observatory hosting the Solar Diameter Imager and Surface Mapper (SODISM) telescope, which has continuously observed the Sun from July 2010 and up to March 2014. In order to study the fine structure of the solar surface, it is helpful to apply techniques that enhance the images so as to improve the visibility of solar features such as sunspots or faculae. The objective of this work is to develop an innovative technique to enhance the quality of the SODISM images in the five wavelengths monitored by the telescope at 215.0?nm, 393.37?nm, 535.7?nm, 607.1?nm and 782.2?nm. An enhancement technique using interpolation of the high-frequency sub-bands obtained by Discrete Wavelet Transforms (DWT) and the input image is applied to the SODISM images. The input images are decomposed by the DWT as well as Stationary Wavelet Transform (SWT) into four separate sub-bands in horizontal and vertical directions namely, low-low (LL), low–high (LH), high-low (HL) and high–high (HH) frequencies. The DWT high frequency sub-bands are interpolated by a factor 2. The estimated high frequency sub-bands (edges) are enhanced by introducing an intermediate stage using a Stationary Wavelet Transform (SWT), and then all these sub-bands and input image are combined and interpolated with half of the interpolation factor α/2, used to interpolate the high-frequency sub-bands, in order to reach the required size for IDWT processing. Quantitative and visual results show the superiority of the proposed technique over a bicubic image resolution enhancement technique. In addition, filling factors for sunspots are calculated from SODISM images and results are presented in this work. 相似文献
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David Auslander Joshua Cermenska Gregory Dalton Mauricio de la Pena C. K. H. Dharan William Donokowski Robert Duck Jonghak Kim David Pankow Alec Plauche Mustapha Rahmani Stephen Sulack Tien Fak Tan Paul Turin Tyler Williams 《Space Science Reviews》2008,141(1-4):185-211
The five “Time History of Events and Macroscale Interactions during Substorms” (THEMIS) micro-satellites launched on a common carrier by a Delta II, 7925 heavy, on February 17, 2007. This is the fifth launch in the NASA MeDIum class EXplorer (MIDEX) program. In the mission proposal the decision was made to have the University of California Berkeley Space Sciences Laboratory (UCB-SSL) mechanical engineering staff provide all of the spacecraft appendages, in order to meet the short development schedule, and to insure compatibility. This paper describes the systems engineering, design, development, testing, and on-orbit deployment of these boom systems that include: the 1 and 2 meter carbon fiber composite magnetometer booms, the 40 and 50 m tip to tip orthogonal spin-plane wire boom pairs, and the 6.3 m dipole stiff axial booms. 相似文献
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