Random Coefficient H-mode Confinement Scalings

TL;DR

This paper applies a novel statistical method to analyze ITER H-mode confinement data, revealing that radiation losses likely cause deviations from theoretical constraints and proposing a new scaling law for energy confinement time.

Contribution

The study introduces a random coefficient regression approach with Maxwell-Vlasov constraints to derive a new empirical scaling law for H-mode confinement.

Findings

Data violate Maxwell-Vlasov constraint at 10-30% significance

Proposed scaling law is similar to ITER89P but with stronger size dependence

Radiation losses likely cause deviations from theoretical constraints

Abstract

The random coefficient two-stage regression algorithm with the collisional Maxwell-Vlasov constraint is applied to the ITER H-mode confinement database. The data violate the collisional Maxwell-Vlasov constraint at the 10-30% significance level, probably owing to radiation losses. The dimensionally constrained scaling, $\tau_E = 0.07192 M^{1/2}$ $(R/a)^{-0.221} R^{1.568} \kappa^{.3} I_p^{.904} B_t^{.201} \bar{n}^{0.106} P^{-0.493}$, is similar to ITER89P with a slightly stronger size dependence.