On the separation of particle flow during pulse laser deposition of heterogeneous materials - A multi-fractal approach

Investigations of Laser Produced Plasmas Generated by Laser Ablation on Geomaterials. Experimental and Theoretical Aspects

“…The result also correlates well with the values of the expansion velocity of the first plasma structure, determined through ICCD fast camera The values of the excitation temperature were found to be in a range of 0-1 eV for the atomic species (i.e., Ca in Sample #1-6264 K, Sample #2-9976 K, Sample #3-6496 K and Sample #4-5800 K) and of about one order of magnitude higher for the ions (i.e., Ca in Sample #1-39440 K, Sample #2-15080 K, Sample #3-32480 K and Sample #4-41760 K). These discrepancies were previously reported by our group in [30,42,43] were they were related to the differential heating of the plume by the incoming laser beam. However, in the LTE conditions we would expect that regardless of the nature of the atom/ion investigated the plasma temperature should have the same values.…”

“…On the other hand, the plume generated on Sample #2 (volcanic rock) presents the highest values for the neutral species, having the highest expansion velocity for the second plasma structure. In literature [30,42,43] the first plasma structure contains mainly ions, while the second and the third one contains mainly neutral species. This view over the nature of the plasma components it is also confirmed by our experimental results.…”

“…During the expansion of a laser produced plasma we can identify three important moments (chronologically): The Coulomb explosion moment, the thermal ejection moment and the cluster formation moment. Each of these moments are defined by three different types of ejection mechanism which lead to the formation of three independent plasma structures [34,36,42,43]. In such a context the dynamics of fast plasma structure generated though Coulomb explosion mechanism would be described by relations (5), (7) and (8) while the dynamics of the slow structure generated through thermal ejection mechanisms are given by relations (6), (7) and (9).…”

Lorenz Type Behaviors in the Dynamics of Laser Produced Plasma

“…Laser ablation embodies a series of phenomena with a complex interconnection between them [1]. For the better understanding of this physical process there have been multiple diagnostics techniques implemented which showcased the particle removal process [2], particle dynamics after ejection [3], plasma formation and expansion [4][5][6], etc. Complementary, theoretical aspects of the process have been steadily showcased in the past 30 years [7][8][9].…”

“…In the past decade there have been some proposals based on a fractal paradigm [12][13][14]. These attempts were focused on the behavior of the laser produced plasma, mainly on peculiar results like multiple structuring during expansion [6], particle oscillations [5] and temporal and spatial distribution of some plasma parameters [13]. The advantage of representing the laser ablation process in a multifractal space is given by the ease with which we can transition between different interaction scales and different sequences of the process.…”