A system for damping vibration in a drill string can include a valve assembly having a supply of a fluid, a first member, and a second member capable of moving in relation to first member in response to vibration of the drill bit. The first and second members define a first and a second chamber for holding the fluid. Fluid can flow between the first and second chambers in response to the movement of the second member in relation to the first member. The valve assembly can also include a coil or a valve for varying a resistance of the fluid to flow between the first and second chambers.
Pursuant to 35 U.S.C. .sctn.202(c), it is acknowledged that the U.S. government may have certain rights to the invention described herein, which was made in part with funds from the Deep Trek program of the U.S. Department of Energy National Energy Technology Laboratory, Grant Number DE-FC26-02NT41664.