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High harmonic generation in magnetic underdense plasma
, Article Progress in Electromagnetics Research Symposium 2009, PIERS 2009 Beijing, Beijing, 23 March 2009 through 27 March 2009 ; Volume 2 , 2009 , Pages 1030-1032 ; 15599450 (ISSN); 9781618390554 (ISBN) ; Abbasi, F ; Beijing Jiaotong University; MIT Cent. Electromagn. Theory Appl./Res. Lab. Electron.; National Natural Science Foundation of China; The Electromagnetics Academy; The Electromagnetics Academy at Zhejiang University; Zhejiang University ; Sharif University of Technology
Electromagnetics Academy
2009
Abstract
A high intensity laser normal incident (1020 W/cm2) on a vacuum-plasma interface produces high harmonics in reflected components. Efficiency of high harmonics increases with the intensity laser incident. So the non-relativistic velocities of the particles vary to the relativistic velocities. Consequently, electrons in such high fields are predicted to quiver nonlinearly, moving in figure eight patterns, rather than in straight lines, and thus to radiate photons at harmonics of the frequency of the incident laser light. To meet the challenge of high power, short wavelength coherent radiation generation, it is quite to investigate the conditions under which harmonics generation efficiency can...
Modification of Biomedical Imaging Methods in Short Wavelength Infrared Window
, Ph.D. Dissertation Sharif University of Technology ; Kavehvash, Zahra (Supervisor)
Abstract
In recent years, optical biomedical imaging techniques show great potential in noninvasive imaging. Although these methods have many advantages over other biomedical imaging methods (such as Computerized Tomography (CT), Magnetic Resonance Imaging (MRI) and etc.), these techniques confront with some problems such as optical scattering, light absorption and etc. For in vivo imaging, the short-wavelength infrared region (SWIR; 1,000–2,000 nm) provides several advantages over the visible and near-infrared regions: general lack of auto-fluorescence, low light absorption by blood and tissue, and reduced scattering. In this thesis we want to analyze the traditional IR imaging techniques and...
Corrected formulation for estimation of ripple in large aspect ratio tokamaks
, Article Journal of Fusion Energy ; Volume 31, Issue 2 , 2012 , Pages 195-197 ; 01640313 (ISSN) ; Khorasani, S ; Sharif University of Technology
Abstract
The finite number of toroidal field coils of a tokamak destroys the perfect axisymmetry of the device. The coils produce a short wavelength ripple in the toroidal magnetic field strength as a field line follows round the torus, which becomes important in transport and confinement properties of plasma. Hence, a quick and accurate estimation of ripple becomes important. We have noticed that a previously reported analytical formulation by Princeton Plasma Physics Laboratory team is not applicable to our large aspect ratio tokamak, and have devised a slightly modified form which has greatly improved the accuracy of the analytical fit