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Observation of a second critical field for negative ions in He II

Research output: Contribution to Journal/MagazineJournal articlepeer-review

<mark>Journal publication date</mark>28/07/1976
<mark>Journal</mark>Journal of Physics C: Solid State Physics
Issue number14
Pages (from-to)L371-L375
Publication StatusPublished
<mark>Original language</mark>English


We have measured the drift velocity v of negative ions in He I1 near 1 K, under a pressure of 25 bar, for electric fields E up to 17 kV/cm. Beyond Ec1, the critical field for creation of stable charged vortex rings, we have observed a second critical field Ec2 at which v passes through a minimum and then starts to increase again. Numerical values of the rate nu at which rings are nucleated, and of the rate P at which the ions escape from the rings again when E > Ec2, are calculated from the experimental data.