Scaling laws for the effective charge of heavy ions penetrating gas or plasma targets
Until now, a theoretical derivation of scaling laws for the effective charge Z(eff) of heavy ions penetrating matter has been lacking, although for cold gaseous targets there are well-established empirical laws relating Z(eff) to the velocity and nuclear charge of the projectile ion, the nuclear charge of the target atoms, and the scaling exponents gamma and delta. It is shown that the scaling exponents may be derived from an investigation of loss and capture rates. The treatment is based on the Bohr-Lamb criterion. This very crude criterion yields gamma = 2/3. The new analysis allows the formulation of a modified criterion, yielding gamma = 0.528 for cold gas, which deviates by only 2% from the often-used empirical Betz formula. The dependence on Z(t) in cold gas is oscillatory and cannot be described by a simple exponent delta. The treatment is also applied to a fully ionised plasma.
Bibliographic Reference: Article: Laser and Particle Beams, Vol. 8 (1990) No. 4, pp. 643-658
Record Number: 199110652 / Last updated on: 1994-12-02
Original language: en
Available languages: en