Abstract: "This report presents the characteristics incorporated in the design of a ballistic rocket system that is capable of carrying recoverable payloads varying in weight from 75 to 200 pounds to altitudes of 600,000 to 1,000,000 feet (msl)."

In choosing a model to describe the behavior of a plasma, a balance must be maintained between the simplicity of a macroscopic description and the detail in a microscopic description. In an ordinary gas, the criterion for behavior as a continuum is that the mean-free-path be small. In a plasma there is a similar criterion; other lengths (Debye, Larmor) may complicate the macroscopic equations but will not destroy their validity. An entirely different criterion (in a collisionless plasma) is that the Larmor radius be small. A consistent treatment of just the lowest order guiding-center particle motion is sufficient to yield, with a minimum of computation, both a microscopic theory (guiding-center gas) and a macroscopic continuum theory (guiding-center fluid). A comparison shows why certain types of arguments conventionally phrased in microscopic terms are exactly equivalent to a potentially less exact macroscopic analysis. (auth)