A brief history of negative triangularity tokamak plasmas

This review is devoted to tokamak plasmas with a cross sectional shape featuring negative triangularity, which appear to hold great promise as a candidate reactor configuration owing to their improved confinement. A brief historical perspective of its role in the worldwide magnetic fusion program is offered before reviewing theoretical predictions and experimental results on both magneto-hydrodynamic stability and turbulent transport. The material covers more prominently the confined plasma region, while limited work in the published literature is devoted to the scrape-off layer and plasma-wall interactions. A discussion on the suitability of this plasma shape in future reactors concludes the paper.