We study theoretically the stability of flow in superfluid 3He-A. The calculations are done using a one-dimensional model where the order parameter depends only on the coordinate in the direction of the superfluid velocity v_s. We concentrate on the case that the external magnetic field H is perpendicular to v_s, where only few results are available analytically. We calculate the critical velocity v_c at which the superflow becomes unstable against the formation of continuous vortices. The detailed dependence of v_c on the temperature and on the form of the underlying orbital texture l(r) is investigated. Both uniform and helical textures and two types of domain-wall structures are studied. The results are partially in agreement with experiments made in a rotating cylinder.
@article{arxiv.cond-mat/0003210,
title = {One-Dimensional Textures and Critical Velocity in Superfluid 3He-A},
author = {J. Kopu and R. Hänninen and E. V. Thuneberg},
journal= {arXiv preprint arXiv:cond-mat/0003210},
year = {2009}
}