Visual and spectroscopic observations were done on laser induced toroidal helium plasmas to determine its geometric properties as well as get an estimate of the temperature. These measurements were...Show moreVisual and spectroscopic observations were done on laser induced toroidal helium plasmas to determine its geometric properties as well as get an estimate of the temperature. These measurements were combined in an effort to gain insight into its underlying thermodynamic processes. At 10μs after creation, the torus was found to have a temperature in the order of 2500K, decreasing to 1000K at 50μs. During this period the volume of the torus increased by a factor in the order of 2.5. It was investigated whether this drop in temperature and increase in volume would follow a model of adiabatic expansion. A least squares fit gave a value of the adiabatic constant of γ = 1.21. More observations must be done to increase the accuracy of these values in order to make substantive conclusions.Show less
