Low frequency, coherent density fluctuations have been studied for three typical magnetic configurations in the helical axis stellarator SHEILA using Langmuir probe techniques. The parametric dependence, the threshold magnetic field, the frequency spectrum and the spatial structure of the fluctuations are measured experimentally. Mode ana!yses are made in a magnetic coordinate system. Both the mode numbers thus obtained and the smallness of the directly measured values of k,, ( k i l k , -100) indicate