  Superconductor--semiconductor hybrid devices are currently attracting much
attention, fueled by the fact that strong spin--orbit interaction in
combination with induced superconductivity can lead to exotic physics with
potential applications in fault-tolerant quantum computation. The detailed
nature of the spin dynamics in such systems is, however, often strongly
dependent on device details and hard to access in experiment. In this paper we
theoretically investigate a superconductor--normal--superconductor junction
based on a two-dimensional hole gas with additional Rashba spin
orbit--coupling, and we focus on the dependence of the critical current on the
direction and magnitude of an applied in-plane magnetic field. We present a
simple model, which allows us to systematically investigate different parameter
regimes and obtain both numerical results and analytical expressions for all
limiting cases. Our results could serve as a tool for extracting more
information about the detailed spin physics in a two-dimensional hole gas based
on a measured pattern of critical currents.
