Fast magnetic compression is investigated in the high voltage belt pinch at two initial densities ne0=3×1013 cm−3 and ne0=7×1013 cm−3. At the lower density the electrons are heated to 3 keV in the piston region, the ions trapped in the piston obtaining an energy of 0.7 keV. A third of the ions are reflected off the piston attaining an energy of 2.5 keV. At the higher initial density a central β=1 plasma is formed. Electrons are heated to 1 keV in the sheath, the piston ions obtaining an energy of 0.4 keV. The degree of ion reflection is 60%. Ion acoustic turbulence in both cases dominates the implosion phase and gives rise to anomalous field diffusion and electron heating. Steep electron density and temperature gradients decisively enhance the effective drift velocity for wave growth. The experimental results are compared with numerical calculations using a hybrid code which includes anomalous transport. Scaling studies with the hybrid code in a wider density range show, in agreement with experiment, increasing efficiency of shock heating for higher initial densities due to increasing ion reflection.