A FEASIBILITY STUDY OF THE MEASUREMENT OF ION DENSITIES BEHIND AIR SHOCKS BY INTRODUCING SMALL AMOUNTS OF LITHIUM VAPOR

摘要

Preliminary experiments indicated that ionization equilibrium is attained in the shock tube behind strong shocks in argon and that the boundary-layer appears to electrically insulate the gas from the metal tube walls.nThe anomalous method was used to measure the amounts of lithium vapor injected into the shock heated air and it is concluded that concen¬trations of 300 ppm could be maintained within a factor of two, Experi¬mental data is presented which suggests that the presence of the lithium vapor has no great effect upon either the vibrational relaxation rate of nitrogen or the overall dissociation rate of oxygen. Interferometric evidence indicated that the bulk dissociation processes did equilibrate behind M 18 shock waves in air although Stark measurements by the 460 3Å lithium line suggest that ionic equilibrium is not attained.