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Full-Text Articles in Physics

Subpicosecond Thomson Scattering Measurements Of Optically Ionized Helium Plasmas, T. E. Glover, Thomas D. Donnelly, E. A. Lipman, A. Sullivan, R. W. Falcone Jul 1994

Subpicosecond Thomson Scattering Measurements Of Optically Ionized Helium Plasmas, T. E. Glover, Thomas D. Donnelly, E. A. Lipman, A. Sullivan, R. W. Falcone

All HMC Faculty Publications and Research

We present the first subpicosecond time-resolved temperature measurements of plasmas produced by high-intensity optical ionization. Thomson scattering is used to measure electron and ion temperatures of helium plasmas created by 125 fs, 800 nm laser pulses focused to an intensity of 2 × 1017 W/cm2. We find that the electron temperature is accurately predicted by a tunneling ionization model. The measured ion temperature is consistent with direct heating by the laser pulse.


Experimental Stark Shift Of Several Nii And Oii Spectral Lines, Mara Scepanovic, Vladimir Milosavljevic, Stevan Djenize, Mihajlo Platisa, Jaroslav Labat Jun 1994

Experimental Stark Shift Of Several Nii And Oii Spectral Lines, Mara Scepanovic, Vladimir Milosavljevic, Stevan Djenize, Mihajlo Platisa, Jaroslav Labat

Articles

Stark shift of four NII and seven OII spectral lines have been measured for the first time in the linear low pressure pulsed arc plasma and compared with existing theoretical values.


Tabletop X-Ray Lasers, D. C. Eder, P. Amendt, L. B. Dasilva, R. A. London, B. J. Macgowan, D. L. Matthews, B. M. Penetrante, M. D. Rosen, S. C. Silks, Thomas D. Donnelly, R. W. Falcone, G. L. Strobel May 1994

Tabletop X-Ray Lasers, D. C. Eder, P. Amendt, L. B. Dasilva, R. A. London, B. J. Macgowan, D. L. Matthews, B. M. Penetrante, M. D. Rosen, S. C. Silks, Thomas D. Donnelly, R. W. Falcone, G. L. Strobel

All HMC Faculty Publications and Research

Details of schemes for two tabletop size x‐ray lasers that require a high‐intensity short‐pulse driving laser are discussed. The first is based on rapid recombination following optical‐field ionization. Analytical and numerical calculations of the output properties are presented. Propagation in the confocal geometry is discussed and a solution for x‐ray lasing in Li‐like N at 247 Å is described. Since the calculated gain coefficient depends strongly on the electron temperature, the methods of calculating electron heating following field ionization are discussed. Recent experiments aimed at demonstrating lasing in H‐like Li at 135 Å ...


X-Rays From Microstructured Targets Heated By Femtosecond Lasers, S. P. Gordon, Thomas D. Donnelly, A. Sullivan, H. Hamster, R. W. Falcone Apr 1994

X-Rays From Microstructured Targets Heated By Femtosecond Lasers, S. P. Gordon, Thomas D. Donnelly, A. Sullivan, H. Hamster, R. W. Falcone

All HMC Faculty Publications and Research

We have demonstrated efficient conversion of ultrashort-pulse laser energy to x rays with energies above 1 keV, using laser-produced plasmas generated on a variety of microstructured surfaces. Lithographically produced grating targets generated 0.1 mJ of kilo-electron-volt x rays, and porous gold and aluminum targets emitted 1 mJ. This represents an improvement of a factor of 100 over flat targets. The K-shell emission spectrum of porous aluminum was composed primarily of heliumlike spectral lines.