Understanding, Triggering and Controlling I-mode like enhanced confinement regimes using Cross Phase mechanisms

The enhanced confinement offered by I-modes and similar new transport regimes offer improved confinement properties with reduced density limit issues and potentially better control. We have proposed differential cross-phase modification as a possible mechanism for different transport in different channels. This is investigated theoretically with a reduced fluid-kinetic hybrid model which illustrates a mechanism for varied cross phase different regimes. Nonadiabatic particle responses incorporate thermodiffusive pinch physics for electrons in ITG and FLR effects for ions in ETG. Moving from ITG dominated regime to an ETG dominated regime the pinch can be dominant or sub-dominant controlling the particle transport and pump out. Computationally, this is investigated with a dynamical transport model. By including in this transport model a model for cross phase effects, due to multiple instabilities, between the transported fields such as density and temperature, we can investigate whether the dynamics of more these continuous transitions such as the I-mode can be captured and understood. If correct this could have broad implications for transport in many systems. Finally, we investigate the control knobs for triggering and controlling these promising regimes.