New kind of ballooning modes with non-separable (in space and time) amplitudes: relevance to astrophysics and non-thermal fusion

New tridimensional plasma structures, that are oscillatory and classified as non-separable ballooning modes, can emerge in inhomogeneous plasmas and undergo resonant mode-particle interactions, e.g., with a minority population, that can lead them to modify their spatial profiles. Thus, unlike the case of previously known ballooning modes their amplitudes are not separable functions of space and time. The relevant resonance conditions are intrinsically different from those of the well-known Landau conditions for (ordinary) plasma waves: they involve the mode geometry and affect different regions of the distribution in momentum space at different positions in configuration space. The novel resonant mode-particle interactions constitute a direct (linear) process to exchange energy between different populations without the inefficiencies of nonlinear coupling processes. The new ballooning modes are relevant to circumbinary disks associated with pairs of black holes and to fusion burning plasmas that include an initially thermal population of fusion reacting nuclei and a population of high energy nuclei (reaction products). It is reasonable to expect that the distributions of the reacting nuclei in momentum space will not remain strictly Maxwellian and that the resulting reaction rates will be different from those evaluated for (conventional) thermalized plasmas.