Universality of discontinuous bifurcations in collisionless dynamics

We investigate the universality in collisionless nonlinear dynamics of a codimension-two bifurcation where two eigenvalues collide at the origin, and two lines of continuous bifurcation and discontinuous jump meet. Through linear analysis and direct numerical simulations, we show that this bifurcation does occur, both for two-dimensional shear flows and for repulsive systems mimicking plasmas.