  Nuclear fusion could offer clean, abundant energy. However, managing the
immense power exhausted from the core fusion plasma towards the divertor
remains a major challenge. This is compounded in emerging compact reactor
designs which promise more cost-effective pathways towards commercial fusion
energy. Alternative divertor configurations (ADCs) are a potential solution to
this challenge. In this work, we demonstrate exhaust control in ADCs for the
first time, on MAST-U. We employ a novel diagnostic strategy for the neutral
gas buffer which shields the target. Our work shows that ADCs tackle key risks
and uncertainties in realising fusion energy: 1) an enlarged operating window
which 2) improves exhaust control through the absorption of transients which
can remove the neutral shield and damage the divertor, 3) isolation of each
divertor from other reactor regions, enabling combined control. This showcases
real-world benefits of alternative divertors for effective heat load management
and control in reactors.
