Neutral and ion beam interactions with laser ablation plasmas

The authors are investigating neutral or ion beam interactions with independently-produced laser ablation plasmas. In these experiments a Q-switched ruby laser generates a dense carbon ablation plasma from a solid target. The laser ablation plasma has been characterized by probe measurements to have densities in the range of 1015 to 1017 cm-3 and temperatures of 20-30 eV. Expansion velocities of the laser ablation plasma have also been measured to be in the range of 1 to 6 cm/μs. The duopigatron accelerates a 5 to 20 kV hydrogen ion beam which may be converted to a neutral beam in a charge exchange cell. Ion beam drain current is in the range 0.2 to 0.4 A. The orientation of the apertured particle beam is perpendicular to the laser beam such that the particles pass through the dense region of the ablation plasma. Transmitted particle flux is measured by a secondary emission particle detector. Preliminary results indicate that significant particle beam attenuation occurs in traversing even a small thickness of dense carbon plasma. An applied-B magnetically insulated diode has been constructed in order to investigate the interaction of higher energy (100-500 kV), higher current ion beams with dense laser ablation plasmas