Browsing by Author "Laha, Sampad"

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    Ion dynamics in strongly coupled plasmas
    (2007) Laha, Sampad; Killian, Thomas C.
    A study of ion dynamics in strongly coupled ultracold neutral plasma (UCNP) is presented here. Plasma is created by photo-ionizing laser-cooled Sr atoms. Immediately after photo-ionization, the correlation between the ion and the electron temperature and density dictate the evolution of the plasma. By extracting the ion's total energy and temperature, and studying their variation with position and time we can get information about the dynamics of the plasma. To do this we use absorption imaging, and for the first time in UCNP, fluorescence imaging and spectroscopic diagnostics, the results of which are presented in this thesis. Using the imaging techniques, we can also study the size change of the plasma with time, which is described by all exact solution of the Vlasov equations for appropriate initial conditions. Also, using fluorescence imaging and spatially resolved spectroscopy, we are able to separate the thermal temperature of ions from the kinetic energy due to expansion and show that the temperature of ions decreases at later times due to adiabatic cooling.
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    Kinetic Energy Oscillations in Annular Regions of an Ultracold Neutral Plasma
    (2005) Laha, Sampad; Killian, Thomas C.; Dunning, F. Barry; Duck, Ian M.
    A study of ion oscillations in the annular regions of a strontium plasma is reported._x000D_ An ultracold neutral plasma is formed by photoionizing the 1 P 1 electrons using a_x000D_ pulsed dye laser' and absorption spectroscopy is done on the 2 S ½ - 2 P ½ transition