Shock‐heated plasmas were produced by focusing 1‐ns 1.06‐&mgr;m laser pulses to intensities of 2×1012W/cm2on 100‐&mgr;m‐diam lithium wires. Interferograms and shadowgrams produced with 1‐ns 0.53‐&mgr;m pulses indicate two distinct phases in the plasma expansion. The first phase is a spherical core of dense plasma produced by a shock propagating through the wire, normal to the axis of the wire, and along the laser beam. Interferometric measurements of the expansion and drift velocity of this phase indicate that the initial pressure behind the shock was 1.4–1.9 Mbar, the compression was 2.6–4.2, the shock velocity was (2.1–2.2) ×106cm/s, and the fluid velocity was (1.3–1.6) ×106cm/s. The second phase is an approximately cylindrical column of partially ionized material produced by shocks propagating along the wire. Shadowgrams show that the velocities of these shocks were greater than 1.7×106cm/s.