An apparatus for monitoring behavior of a plasma gun, comprising: a process controller structured and arranged to control operational parameters of the plasma gun; a voltage sensor (14, 105) structured and arranged to sample a gun voltage of the plasma gun; a data processor configured to analyze the sampled gun voltage, to identify amplitude peaks, and to produce a pattern representing the identified amplitude peaks; a memory configured to store known gun operating patterns; and wherein the apparatus further comprises: a comparer configured to compare the produced pattern to the stored known gun operating patterns, including at least a set of known normal operation patterns and a set of known abnormal operation patterns, wherein, when the produced pattern corresponds to a known normal operation pattern, the behavior of the plasma gun is indicated as normal, wherein, when the produced pattern does not correspond to any of the known normal operation patterns in the set of known normal operation patterns, the comparer is configured to compare the produced pattern to known abnormal operation patterns in the set of known abnormal operation patterns, and wherein, when the produced pattern corresponds to a known abnormal operation pattern, the behavior of the plasma gun is indicated as abnormal and the process controller is instructed to perform a corrective action. a process controller structured and arranged to control operational parameters of the plasma gun; a voltage sensor (14, 105) structured and arranged to sample a gun voltage of the plasma gun; a data processor configured to analyze the sampled gun voltage, to identify amplitude peaks, and to produce a pattern representing the identified amplitude peaks; a memory configured to store known gun operating patterns; and wherein the apparatus further comprises: a comparer configured to compare the produced pattern to the stored known gun operating patterns, including at least a set of known normal operation patterns and a set of known abnormal operation patterns, wherein, when the produced pattern corresponds to a known normal operation pattern, the behavior of the plasma gun is indicated as normal, wherein, when the produced pattern does not correspond to any of the known normal operation patterns in the set of known normal operation patterns, the comparer is configured to compare the produced pattern to known abnormal operation patterns in the set of known abnormal operation patterns, and wherein, when the produced pattern corresponds to a known abnormal operation pattern, the behavior of the plasma gun is indicated as abnormal and the process controller is instructed to perform a corrective action. a comparer configured to compare the produced pattern to the stored known gun operating patterns, including at least a set of known normal operation patterns and a set of known abnormal operation patterns, wherein, when the produced pattern corresponds to a known normal operation pattern, the behavior of the plasma gun is indicated as normal, wherein, when the produced pattern does not correspond to any of the known normal operation patterns in the set of known normal operation patterns, the comparer is configured to compare the produced pattern to known abnormal operation patterns in the set of known abnormal operation patterns, and wherein, when the produced pattern corresponds to a known abnormal operation pattern, the behavior of the plasma gun is indicated as abnormal and the process controller is instructed to perform a corrective action.