Laboratory plasma dynamo at low magnetic Prandtl number
In plain words
Laser experiments have shown turbulent plasma amplifying a magnetic field when the gas's viscosity and electrical resistance are comparable. In stars and planets resistance is much larger than viscosity, and no laboratory plasma has shown a dynamo in that regime.
Precise statement
Laser-plasma experiments (2018, 2021) amplified seed fields by fluctuation dynamo at magnetic Prandtl number $\mathrm{Pm} = \mathrm{Rm}/\mathrm{Re}$ near 1. Determine experimentally whether the fluctuation dynamo operates in a plasma with Pm much less than 1 and measure its critical Rm and growth rate. An answer is a measured dynamo threshold compared with the MHD prediction of a higher critical Rm at low Pm.
What would settle it
A laboratory plasma at Pm much less than 1 and Rm above the predicted threshold, with time-resolved field measurements showing exponential growth.