A fate of nonlinear evolution of drift waves: Excitation of nonlinear breathers

Abstract

We present the evidence that drift waves can develop into nonlinear breathers. The theoretical analysis predicts that drift waves with secondary flow can excite the nonlinear breather through modulational instability. It is found that the simultaneous modulation of both amplitude and phase is a relevant feature of breather excitation. These features are used to elucidate the excitation of drift breather in a linear plasma experiment. The drift breathers are found to be excited frequently and intermittently. The transient increase in the transport flux is also demonstrated. We argue that there exists a critical condition on the wave amplitude for breather excitation.

Breathing impure plasmas

“…Since then, breathers are observed in various systems, such as optical fibers [15], dusty (complex) plasmas [16]. Breathers are also excited from drift waves, which we call as a drift breather [17]. The excitation of drift breathers are confirmed in basic experiments, and transient increase of particle flux is also confirmed in data analysis.…”

“…In this sense, breathers may be easier to observe in plasmas with weak magnetic shear, such as shear-less stellarators, basic linear experiments, etc. Indeed a previous study reports the excitation of breathers and enhancement of turbulent particle flux via data analysis from the linear magnetized plasma experiment, PANTA [17,35]. A similar experiment and data analysis may be performed with impurities.…”