Interpretative and predictive modelling of Joint European Torus collisionality scans

Transport modelling of Joint European Torus (JET) dimensionless collisionality scaling experiments in various operational scenarios is presented. Interpretative simulations at a fixed radial position are combined with predictive JETTO simulations of temperatures and densities, using the TGLF transport model. The model includes electromagnetic effects and collisions as well as □(→┬E ) X □(→┬B ) shear in Miller geometry. Focus is on particle transport and the role of the neutral beam injection (NBI) particle source for the density peaking. The experimental 3-point collisionality scans include L-mode, and H-mode (D and H and higher beta D plasma) plasmas in a total of 12 discharges. Experimental results presented in (Tala et al 2017 44th EPS Conf.) indicate that for the H-mode scans, the NBI particle source plays an important role for the density peaking, whereas for the L-mode scan, the influence of the particle source is small. In general, both the interpretative and predictive transport simulations support the experimental conclusions on the role of the NBI particle source for the 12 JET discharges

The Derivative of an Orthogonal Matrix of Eigenvectors of a Symmetric Matrix.

AbstractThe authors supply the derivative of an orthogonal matrix of eigenvectors of a real symmetric matrix. To illustrate the applicability of their result they consider a real symmetric random matrix for which a more or less standard convergence in distribution is assumed to hold. The well-known delta method is then used to get the asymptotic distribution of the orthogonal eigenmatrix of the random matrix

Minimal Moments and Cumulants of Symmetric Matrices: An Application to the Wishart Distribution

An algorithm is proposed and notions defined to determine the minimal sets of all possible higher order moments and cumulants of a random vector or a random matrix. The main attention has been paid to the case of symmetric matrices. Using the introduced notions, cumulants of arbitrary order for the Wishart distribution have been obtained.