Answers are grounded in this paper and cite their sources.
It was previously shown that at temperatures {≥}0.36^∘{}K and pressures >12 atm negative ions in He II could be accelerated until they emitted rotons at velocities of about 50 m/sec. We find that at temperatures {≤}0.3^∘{}K negative ions produce only vortex rings at pressures up to 16 atm.
No takes yet. Share an insight, caveat, or question.
Donald A. Neeper (1968) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: