Astable regime in electrosprays.

Astable regimes are common in nonlinear systems ranging from electrooptic devices to cardiac rhythms under environmental stress. Electrosprays exhibit three main axial regimes (dripping, pulsating, and cone-jet). It is generally accepted that the transition between the pulsating and cone-jet regimes is sudden, accompanied by an abruptly enhanced spray current. Here we present an alternative to this scenario, in which the electrospray follows a new chaotic astable path to the cone-jet regime. The astable regime could be explained as a result of transitions between a limit cycle (pulsating regime) and a fixed point (cone-jet regime) in a subcritical Andronov-Hopf bifurcation due to small external perturbations (noise). With the introduction of this regime, a broader view of the diverse axial regimes becomes possible based on nonlinear dynamics that enables their consistent classification.