Observations by the Hinode satellite of quiescent prominences have revealed in great detail the dynamics of plumes rising through the prominence material. These plumes, created by the magnetic Rayleigh-Taylor instability, rise through the prominence material compressing it as they go. In this talk I will show how the growth rate for the linear instability and the compression at the head of the rising plume in the nonlinear regime provide diagnostic tools for investigating both the plasma beta and the magnetic field direction in the prominence. These methods will be compared to observations of plumes with both Doppler velocity and magnetic field measurements (both strength and direction) by Orozco Suarez et al (2014) to confirm their validity. It is through application of these new methods that I beleive we will be able to make great strides in understanding the role of the magnetic field in the small-scale dynamics of quiescent prominenceswithout the need for complex polarization measurements.