Experimental Evidence for Coronal Mass Ejection Suppression in Strong Stellar Magnetic Fields.

Solar coronal mass ejections (CMEs) are routinely observed, but as of yet there exist few convincing detections of stellar CMEs. A reason for this could be that the stronger magnetic fields of these stars, compared to that of our Sun, would prevent CME to form and escape. Here we combined astrophysical simulations, measurements of scaled high-energy laser-driven plasma flows, and 3D magnetohydrodynamic modeling to test this hypothesis. Simulations show that, in a 100 G stellar dipole field, low-plasma β CMEs become magnetically confined. In the laboratory, a laser-produced plasma stream scaled to stellar CME conditions propagates freely at low applied magnetic fields (approximately 30 G stellar equivalent), but becomes unstable and halts entirely when the field is increased to 3×10^{5}  G (i.e., a 100 G equivalent). Analytical estimates and numerical simulations suggest that the sudden disruption of the flow is induced by a kink instability. Even though the laboratory environment does not fully reproduce the complex magnetic flux-rope topology of CMEs, these results provide the first laboratory-scale evidence that strong stellar magnetic fields can fully suppress CME propagation, offering a physical explanation for their lack in stellar observations and highlighting the role of magnetic confinement in stellar evolution and exoplanet space weather.