On energy conservation laws in the drift-reduced Braginskii model

A revision of the drift-reduced Braginskii model is presented, focusing on its practical implementation in numerical codes, and systematically analyzing the effect of several commonly-used approximations on energy conservation. As a practical example, the effect of the approximations is quantified in the GBS code. By dropping the most important approximations and related energy sinks, the simulation shows increased transport levels and a target heat flux with closer agreement to experimental observations.