Tokamak transport based on the 13-moment model

A new model for collisional transport in a tokamak plasma is analysed. This model is obtained from Grad's 2-fluid 13-moment equations by estimating the order of magnitude of the various effects and neglecting those that are small. The model includes small particle flows, pressure anisotropy and temperature variation within flux surfaces. A formal solution is calculated that satisfies the model equations to O(m_e/m_i). These solutions are found to evolve on a time scale T_em_i/m_e ≈ 50 ms.