Using intense magnetic pressure, a method was developed to launch flyer plates to velocities in excess of 20 km/s. This technique was used to perform plate‐impact, shock wave experiments on cryogenic liquid deuterium (LD2) to examine its high‐pressure equation of state (EOS). Using an impedance matching method, Hugoniot measurements were obtained in the pressure range of 22–100 GPa. The results of these experiments disagree with previously reported Hugoniot measurements ofLD2in the pressure range above ∼40 GPa, but are in good agreement with first principles,ab‐initiomodels for hydrogen and its isotopes. Additionally, a novel approach was developed using a wave reverberation technique to probe density compression ofLD2along the principal Hugoniot. Relative transit times of shock waves reverberating within the sample are shown to be sensitive to the compression due to the first shock. Results in the range of 22–75 GPa corroborate the ∼4 fold density compression inferred from the impedance matching Hugoniot measurements, and provide data to differentiate between proposed theories for hydrogen and its isotopes. © 2004 American Institute of Physics