The use of short range order parameters in determining the bubble-bubble interaction range

The range of bubble-bubble interactions on the major loop was determined from studies in which a 157 bit bubble train was circulated around the major loop at a bias field selected to collapse most of the bubbles within about 12 hours of continuous operation. The progress of the decay of the bubble train was monitored by replicating and reading once every 500 major loop rotations. A comparison of two successive reads provided discrimination against soft errors. The bit sequence was printed each time a hard error was encountered. Short range order parameters were used to determine staistically whether the collapsed bubbles were randomly positioned. Bubbles initially spaced two periods apart exhibited short range order during the decay. However, in similar experiments with bubbles initially spaced four periods apart, a random decay was observed. It was thus concluded that there is bubble-bubble interaction on the major loop with a range of two to three periods.