Experiments with a magnetic well using a gun-injected plasma are described. Typical parameters are Bz ≃ 1.8 kG, n = 5×l012 cm−3, Ti = 1.5 keV, Te = 15 eV and length of trap = 1.5 m. A wide range of diagnostics have been used including atomic beams of potassium, krypton and xenon for measuring ∫ n dℓ and Te. An initial rapid loss of plasma is associated with the method of filling the trap which results in an ion velocity space distribution peaking near the loss cone angle; however, detailed analysis shows that the ion scattering process is not caused by Coulomb collisions although the energy transfer rate between ions and electrons is not inconsistent with classical collisions. Electric field fluctuations of ∼ 1 V · cm−1 near ωci are observed.