Rayleigh Taylor instability in the solar corona loop experiment*

We are observing a Magneto Rayleigh Taylor instability (MRTI) in a laboratory experiment that simulates solar corona loops. Unlike a previous experiment in our lab where MRTI instigated by the effective gravity of a kink instability was observed $^{\mathrm{[1]}}$, here the acceleration from the hoop force acting on the loop provides the effective gravity. Detailed measurements indicate a scaling where the observed axial wavelength $\lambda $ increases when a larger bias magnetic field is used. This scaling is possibly consistent with the theoretical MRTI growth rate $\gamma ^{2}=gk-\frac{\left( {{\rm {\bf k}}\cdot {\rm {\bf B}}_{{\rm {\bf 0}}} } \right)^{2}}{\mu_{0} \rho }$, because this theoretical growth rate implies that if ${\rm {\bf k}}$is parallel to ${\rm {\bf B}}_{{\rm {\bf 0}}} $ (i.e., undular mode), the fastest growing mode has $\lambda =\frac{2\pi }{k}=\frac{4\pi {\rm {\bf B}}_{{\rm {\bf 0}}}^{2}}{\mu_{0} \rho g}$. We are also exploring other features such as appearance of a kink after the MRTI, different experiment parameters and whether a fast magnetic reconnection happens during this process. [1] A. L. Moser and P. M. Bellan, Nature 482, 379 (2012).