Product Code: ICAL06_M1202

Study of Magnetic Confinement in Laser-induced Plasmas by Optical Emission Spectroscopy and Fast Photography
Authors:
X.K. Shen, University of Nebraska; Lincoln NE USA
T. Gebre, University of Nebraska; Lincoln NE USA
Yongfeng Lu, University of Nebraska-Lincoln; Lincoln NE USA
Presented at ICALEO 2006

The dynamics and magnetic confinement effects of laser-induced plasmas expanding across an external transverse magnetic field were investigated by optical emission spectroscopy and fast photography. KrF excimer laser pulses with a pulse duration of 23 ns and a wavelength of 248 nm were used to produce plasmas from Cu targets. Various optical emission lines show an obvious enhancement in the intensity of optical emission when a magnetic field of ~0.8 Tesla is applied. Temporal evolution of the optical emission lines shows a continuous enhancement in emission intensity at time delays of 3-20 μs after the incident laser pulse. The enhancement in the optical emission from the Cu plasmas was presumably due to the increase in the effective plasma density as a result of magnetic confinement. Fast photography of the laser-induced Cu plasmas was performed using a Nikon macro lens and Andor intensified CCD camera. It shows that the plasma splits into two parts after gate delay of around 3 μs both with and without a magnetic field. With the presence of a magnetic field, the two parts of the plasma are confined and recombine with each other after gate delay of around 18 μs. While without the presence of a magnetic filed, the two parts keep separated as time delay increases.