At low Scrape-Off-Layer (SOL) density nSOL, a gas puff is frequently applied at Lower Hybrid (LH) heating at JET, in order to increase the LH density and to decrease the reflection coefficient R. However, in absence of a sufficient amount of the neutral gas in front of the grill, the observed reflection coefficient R of the grill can increase as a function of the LH power PLH. This R increase is caused by a decrease of the SOL density nSOL just in front of the grill mouth. Similar effects observed on ASDEX and recently on Tore Supra were explained by expulsion of the plasma from the grill mouth along magnetic field B-lines by ponderomotive forces of the launched LH wave. In order to explore the ponderomotive force effects on JET, the EDGE2D code was now modified in order to include the ponderomotive forces: In the momentum equation for the electron fluid, a net time averaged force acting on electrons due to the LH field gradient was included in EDGE2D. This force expels electrons away from the grill mouth, the ions follow due to the Coulomb charge separation force.