Emission characteristics and stability of laser ion sources
Josef Krása, Andriy Velyhan, Eduard Krouský, Leoš Láska, Karel Rohlena, Karel Jungwirth, Jiří Ullschmied, Antonella Lorusso, Luciano Velardi, Vincenzo Nassisi, Agata Czarnecka, Leszek Ryćhttp://academic.research.microsoft.com/io.ashx?type=5&id=41083289&selfId1=0&selfId2=0&maxNumber=12&query=
A new classification of laser ion sources concerning their pulse-to-pulse reproducibility in the ion emission is proposed. In particular, we distinguish between plasmas according to the electron distribution and changing its characteristics at a laser intensity threshold of 1014W/cm2. Well reproducible continuous pulsed ion currents are typical for the intensity below the threshold. In contrast to this plasma the “two-temperature” plasma arising for the intensity above this threshold shows not only a separation of charges in space and time during the expansion but it also shows outbursts of ions similar to a self-pulsing instability leading to a chaos. The sequence of fast ion outbursts visible on the time-resolved ion currents is sensitive to the details of non-linear interaction of the laser beam with the generated plasma.Analysis of ion sources based on a time-of-flight signal function is applied to quantify their emission characteristics as the hidden partial currents of the ionized species constituting, the total measured current, the centre-of-mass velocity of individual charge states, their abundance and the ion temperature.