Dynamics of plasma corona of laser-irradiated spherical targets

Time-of-flight profile of multiply-charged ion currents produced by a pulse laser

“…Another expression for j (l, t) was derived by Zakharenkov et al [21]. They utilized interferometric techniques to measure plasma electron density distribution as well as its temporal evolution.…”

“…where n i (l 0 , t 0 ) is the early stage ion density at a distance l 0 from the target and at time t 0 from the laser onset time [21][22][23]. The distance, l, of the IC from the target and the time-of-flight, t, are linked to l 0 and t 0 by the relation l/t = l 0 /t 0 .…”

Analysis of time-of-flight spectra of ions emitted from laser-generated plasmas

“…Zakharenkov et al (8) supposed that the ion density n i (l, t) expands adiabatically since the instant t 0 ≈ τ L , where τ L is the laser pulse duration, and assuming the average ion charge-state q to Downloaded by [Simon Fraser University] at 03:01 20 November 2014 be known, they deduced the plasma density from the electron density as ρ(L, t) = n e (L, t) m i /q. Since n e (L, t) ≈ n 0,cr exp(−L/v T t), the time-resolved ion current was deduced to be:…”

“…Moreover, q(t) can be determined only experimentally, for example, with the use of a cylindrical electrostatic ion analyser (CEA) what is a complex diagnostics problem (8,9). Only ions with particular values of mass to chargestate ratio can pass through a CEA's deflection system and reach the detector, for example a windowless electron multiplier, which should be calibrated (10) because the detected ion current is converted into a current of electrons.…”

“…where L/t = L 0 /t 0 , and t 0 is taken as the laser pulse duration and/or the time after which no other acceleration of ions occurs (8,11). The distance L 0 is given by the ion-sound velocity at the instant t 0 .…”