  The response of superconductor-normal-metal-superconductor junctions to
magnetic field is complicated and non-universal because all trajectories
contributing to supercurrent have a different effective area, and therefore
acquire arbitrary magnetic phases. We design an hourglass-shaped Josephson
junction where due to the junction symmetry the magnetic phase of every
trajectory is approximately equal. By doing so we are able to increase a
critical field of the Josephson junction to many flux quanta per junction area.
We then analyse how breaking the symmetry condition increases the sensitivity
of the junction, and show that our device allows to detect supercurrent carried
by ballistic trajectories of Andreev quasiparticles.
