Density determination in the TEXTOR boundary layer by laser-ablated fast lithium atoms
A method is presented which allows a determination of electron density profiles in the plasma boundary of a fusion device up to some 1.0 x E+13 /cm3 within about 100microsec. For this purpose, the complete attenuation of an injected lithium beam is determined by measuring its optical emission profile. The beam is generated by a ruby laser, which ablates small portions of a LiF coating with a thickness of about 1000A from the rear side of a glass substrate. The produced lithium atoms have velocities of 1.0 E6 cm/s and can penetrate into the plasma until n(e) x l is of the order of 1.0 E13 /cm2. For the measurement of the optical emission profile of the excited lithium atoms, a silicon photodiode array camera is used. The emission profile is then converted into an electron density profile with the help of the ionization rate for lithium atoms by electron impact.
Bibliographic Reference: Article: Rev. Sci. Instrum., Vol.59 (1988), No. 4, pp.605-609
Record Number: 198910229 / Last updated on: 1994-12-01
Original language: en
Available languages: en