Solitary holes of negative energy and their possible role in the nonlinear destabilization of plasmas

A new energy expression for a one-dimensional structured Vlasov-Poisson system is presented. It admits the existence of negative energy states caused by electrons and ions which resonantly interact with the self-consistently excited hole structure. In contrast to earlier energy expressions making use of resonant particle effects the contributions of trapped particles are taken into account rigorously without any reference to linear wave solutions. The main conclusion drawn for current carrying plasmas is that structured states of negative energy exist for drift velocities in the linearly stable range, which may destabilize the plasma nonlinearly already at infinitesimal amplitudes. Two numerical experiments are reconsidered and it is argued that the observed growth of an initial seed-like perturbation may be related to the concept of negative energy waves and the associated release of free energy. (C) 2002 American Institute of Physics.