Multifluid equations describing the plasma of vacuum arcs expanding anisotropically from a cathode spot are given and discussed. Some first and preliminary results from an approximate analytical integration of such a system of equations, based on the representation of all plasma parameters by asymptotic power series, are presented and evaluated. Though the dependence of the plasma parameters on the direction (angle /spl thetav/) is weak, the inclusion of angular terms and angular equations changes some results significantly, compared with the experiences from usually 1-D models. While the basic radial dependence (r) of the terms /spl sim/r/sup -2k/5/, k=0,1,2..., remains the same as in 1-D theories, we now get an angular dependence /spl sim//spl thetav//sup 2/ of the parameters in a first approximation, with positive factors, i.e., a flattening of the whole plasma distribution. However, with analytical solutions of higher flexibility, cos-like distributions are possible as well. The final kinetic energy of the plasma ions in the case of Cu arc spots is caused by the electric field within the plasma (contributing approximately 27%), the ion pressure gradient (/spl sim/24%), and the electron-ion friction (plasma resistivity, /spl sim/49%) in directions near to the discharge axis. Again, similar to the results from 1-D models. With an approach to the cathode surface (/spl thetav//spl rarr//spl pi//2), the plasma flow becomes ambipolar. Finally, some further possibilities which are available with the help of this model are discussed.
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