An investigation of projective integration methods for scrape off layer density modification by nonlinear RF ponderomotive effects.*

Fusion relevant plasmas exhibit multiscale processes in both space and time. Here we present progress on the application of projective integration methods to address the temporal multiscale issue. As a test case, we use the scenario of electron density modification via parallel ponderomotive effects during the application of high power RF waves in the scrape off layer of magnetic confinement fusion devices. In this scenario there is a clear separation of timescales between a fast RF oscillatory component to the density, and a subsequent slow non-oscillatory modification. These physics are traditionally addressed by a formal separation of timescales, allowing the comparison of our projective integration treatment to integrating the slow non-oscillatory density modification with that approach.