\title{First order perturbative calculations for a conducting liquid jet in a solenoid} \author{J. Gallardo, S. Kahn, R. B. Palmer, P. Thieberger, R. Weggel} \affiliation{ Brookhaven National Laboratory\\ Upton, NY 11973} \author{ K. McDonald} \affiliation{Princeton University\\ Princeton, NJ 08544} A perturbative calculation is given of the behavior of a continuous jet of conducting fluid as it enters and leaves a solenoidal magnetic field. It is assumed that the changes in direction, jet cross section and velocity are small. If the jet enters the field along, or close, to the axis, then the induced forces are compressive and retarding. The jet slows, suffers an increase in hydrostatic pressure, and increases in diameter; later, the jet re accelerates and elongates. As the jet leaves the field, the hydrostatic pressure becomes negative, and cavitation may occur. If the jet enters at an angle to the axis, there are, in addition, deflections and elliptical deformations of the jet. Formulae are given for these effects and numerical values given for the example of a solenoidal field with a Gaussian axial profile.