# Experimental observations and modelling of intrinsic rotation reversals in tokamaks

## TL;DR

This paper reviews experimental observations and theoretical models of spontaneous intrinsic rotation reversals in tokamaks, highlighting the role of turbulent momentum transport and proposing directions for future research.

## Contribution

It provides a comprehensive synthesis of experimental data across multiple tokamaks and reviews existing theories, offering new insights into the mechanisms behind rotation reversals.

## Key findings

- Turbulent momentum transport is key to rotation reversals.
- Experimental data from AUG, C-Mod, KSTAR, MAST, TCV support the turbulence-based explanation.
- The paper suggests new avenues for investigating intrinsic rotation phenomena.

## Abstract

The progress made in understanding spontaneous toroidal rotation reversals in tokamaks is reviewed and current ideas to solve this ten-year-old puzzle are explored. The paper includes a summarial synthesis of the experimental observations in AUG, C-Mod, KSTAR, MAST and TCV tokamaks, reasons why turbulent momentum transport is thought to be responsible for the reversals, a review of the theory of turbulent momentum transport and suggestions for future investigations.