{'fraction_non_alphanumeric': 0.01989683124539425, 'fraction_numerical': 0.015475313190862197, 'mean_word_length': 4.436582109479306, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Reply to Comments of Clements and Smy

We would like to start by agreeing with Clements and Smy that the Langmuir probe is a simple and flexible diagnostic tool. What we have attempted to show in our paper is that it can also be used in what are normally considered to be hostile environments, such as welding arcs. When we calculated the parameters necessary for the analysis of the probe characteristics measured in welding arcs we found that we were in an extremely interesting region which was neither thin-sheath collision-dominated (as would be required for continuum analysis) nor in the strictly classical free-fall situation. However, the analysis did show that the mean free path for the ions was such that the number of collisions in the sheath would be few, and for a very thin sheath the total ion current carried by the probe could be reasonably approximated to kneL4, where A is the surface area of the probe. The objection raised by Clements and Smy is that if XD/~, is very small (in our case it is approximately l/lOOO) then the ion current drawn to the probe should be 1000 times larger than that given by our analysis. This assumes that the analysis by Clements and Smy (1970) is applicable to our particular situation, but they have presented no evidence to justify this. In fact, for our calculated mean free paths and sheath thickness, a X D / ~ , of ljl000 would ensure that almost all the ions that crossed the sheath boundary would be collected. If continuum theory were applicable, then the analysis of Lam (1964) would indicate that we would be in the thin-sheath collision-dominated situation where clearly XD/~, would become important. However, one consequence of that analysis is that it does not predict saturation currents, whereas for our probe characteristics (Gick et al 1973, figure 4) above a bias voltage of 20 V the ion current was substantially constant. This leads us to believe that we are not in fact in a region where continuum theory is applicable. However, we do not believe that the probe is having no effect on the plasma; we feel sure that it is. But we do not believe that it can affect the ion current by a factor of 1000; we estimate that the factor is less than 2. Referring to figure 2 of our paper, Clements and Smy have clearly realized that we are working in a region where it would be impossible to draw 1000 times more current as predicted by their analysis; the same point was made by Freeston and Kelk (1970) when they applied the Clements and Smy theory to their experimental results. Also, it is clear from our figure that there is an optimum temperature range for which we would recommend our technique to be used. For low temperatures (below 7000 K) the probe current varies so rapidly with changes in temperature that our technique may not be sufficiently sensitive for the measurement of temperature profiles (this is where we feel the analysis of Clements and Smy is most useful). Also, above about 16 000 K the probe current is virtually independent of temperature, and again the measurement becomes insensitive. This range (7000-16 000 K for argon) is just the range found in many arc applications. The fact that we cannot draw 1000 times more current than predicted by our analysis has promptly been reduced to one order of magnitude by Clements and Smy by some inconclusive points on the effect of gas flow. It is naive of them to say that we do not consider this applicable, and we have in fact applied the flow analysis of a colleague (Thomas 1969) to our situation. We feel that the effect of flow might be the limiting condition to the use of the technique we have proposed, and we are at the moment finding this to be the case for similar probe measurements in high-velocity plasma arcs, but in the arcs we described there is no such problem. We appreciate very much the comments by Clements and Smy and would like to say how highly we regard their very valuable work. However, under the conditions in which we have been working it turned out that certain very simplifying assumptions could be