of quiescent prominence plumes. [@HILL2011] and [@HILL2012] showed how upflows could be created by the 3D mode of the magnetic Rayleigh-Taylor instability acting on the boundary between the Kippenhahn-Schlüter prominence model [@KS1957] and a hot tube inserted into the it. The upflows created were found to be qualitatively similar to the observed plumes.

Observations of the magnetic field of quiescent prominences show the field strength to be in the range $\sim 3$-$30$ G [@LER1989], where the average for polar-crown prominences is $\sim 5$G [@ANHEIN2007]. However, as it is very difficult to observe the prominence magnetic field directly, often other methods to determine the magnetic field of prominences have been employed. One common mechanism has been to extrapolate the photospheric magnetic field to obtain values for the coronal field where the prominence is observed [@DUD2008; @AUL2003]. Another common method is to analyse the oscillatory pattern of filaments [@ISO2006; @PINT2008; @TRIP2009] or filament threads [@LIN2007; @LIN2009] to calculate the magnetic field through the application of wave theory. This is known as prominence seismology [@AGG2012]. In this paper we present a new method to investigate the magnetic field strength relative to the gas pressure by determining the plasma $\beta$ (ratio of gas pressure 