An experimental investigation of double ionisation of helium atoms in collisions with fast, fully stripped ions

Charge-equilibration of Fe ions accelerated in a hot plasma

“…The Bohr's (1948) cross section for the single ionization of an ion/atom by fast, fully stripped ions (e.g., protons) can be cast into a very compact form (Knudsen et al 1984).…”

The ratio of cross sections for double to single ionization of helium by high energy photons and charged particles

“…Of particular interest are those results obtained for projectiles in high charge states at high velocity, v. In the discussion below, regimes of validity are delineated for each of the mechanisms, and ratios of double-to-single ionization cross sections are presented and compared with theoretical predictions. Double ionization of helium by charged particles has been the subject of numerous experimental and theoretical investigations for nearly three decades [Mittleman 1966, Byron and Joachain 1966, Horsdal-Pedersen and Larson 1979, McGuire 1982, Knudsen et al 1984, Andersen et al 1986, 1987, Reading and Ford 1987a, Reading and Ford 1987b, Giese and Horsdal 1988, Kamber et al 1988, Reading et al 1989, Herber et al 1990]. Much ofthe interest in double ionization by charged particles stems from its fundamental nature [Mittleman 1966, Byron and Joachain 1966, McGuire 1982 and its relationship to double ionization by photons [HorsdalPedersen and Larsen 1979, Samson 1990, Levin et al 1991] (see Sec.…”

“…Extensive measurements of double-to-single ionization ratios in the intermediate-to high-velocity regimes are available only for H+ [Knudsen et al 1984, Shah and Gil body 1985 and He2+ [Knudsen et al 1984, Heber et al 1990]. Additionally, there are published data for N7+ [Heber et al 1990], o7+ [Tanis et al 1991a], sB+ [Tanis et al 1991 b ], U90+ [Berg et al 1992], several other highly-charged (not fully-stripped) ions [McGuire et al 1982]; and recent high velocity data for NelO+,Ni28+, and Kr36+ ions obtained by Ullnch et al [ 1993].…”

“…7. (Knudsen et al [1984], Andersen et al [1987], Shah and Gilbody [1985]); open squares-He2+ (Knudsen et al [1984], Andersen et al [1987] and Heber et al [1990]); winged squares-N+l (Herber et al [1990]); open diamonds-()+7 (Tap.is et al [1991a]; starburst-Ne+IO ); X-Si+l3 (Tanis et al [1991b]); crosses -Ni+28 ); winged diamonds -Kr+36 ); fancy crosses-u+90 (Berget al [1992]). The solid line indicates a (v/Z)-2 dependence (see text).…”

“…The solid line indicates a (v/Z)-2 dependence (see text). The dashed line indicates the shakeoff (SO) limit (Z/v = 0.0022) determined by Knudsen et al [1984]. The two-step (TS2), shakeoff (SO), and intermediate (Int.)…”