Vm. Batenin et al., Production of an extended plasma column in vacuum by irradiating a target by a quasi-Bessel beam, QUANTUM EL, 31(5), 2001, pp. 448-452
A technique of focusing the heating radiation was investigated, which makes
it possible to produce an extended (under laboratory conditions, up to 1 m
and over) plasma column and enables an easy output of VUV radiation. A pla
ne solid-state target in vacuum was arranged along the caustic of a conic l
ens (axicon), which focused the laser beam. An analytic dependence, which d
escribes the spatial intensity distribution of the heating radiation in the
case of a nontransparent, partially reflecting target, was derived and exp
erimentally verified. Experiments on the irradiation of an aluminium target
in vacuum with a 5-J, 5-ns pulse of a neodymium-glass laser were performed
. A plasma column up to 30 mm in length and no greater than 10 mum in diame
ter was formed. A rather intense plasma radiation was recorded in the VUV r
ange.