No abstract

In the preceding issue of Tellus were pub- lished the first results of our investigations of cosmic ray orbits in the field of a magnetic dipole. The investigations were carried out by measurements o n a model with particle mo- mentum range corresponding to 1010-eV/c. A detailed description of the apparatus and the performance of the experiment is given in part I of the present paper.

The anisotropy of the cosmic radiation outside the geomagnetic field is discussed and related to various processes in the interplanetary gas. Special attention is given to the effect of the density gradient in the cosmic ray distribution, to the earth's orbital motion and to the motion of the interplanetary gas in the solar system.

The recorded data of diurnal variation of the cosmic ray intensity are analysed. By using the known deflection of the cosmic ray particles in the geomagnetic field (Brunberg and Dattner 1953) and under an assumption of an anisotropy in the primary cosmic radiation, it is shown that the momentum of the primary radiation and the direction of the anisotropy can be determined. The anisotropy is explained as an effect due to the distribution of cosmic ray particles rotating with the solar magnetic field as suggested by H. Alfvén. The diurnal variation is ascribed to the earth's rotation in the anisotropic distribution of cosmic ray particles. The theoretical amplitude of this variation is calculated.

A coaxial plasma gun experiment is described. The gun has an azimuthal bias magnetic field, which is strong compared to the field from the discharge current. The discharge voltage is shown to depend linearly on the bias field, thus defining a velocity that is found to be almost independent of the pressure and the discharge current. This velocity is close to the ``critical velocity'' which has been found in rotating-plasma experiments. The velocity of the current layer is also measured; it is always smaller than or equal to the critical velocity and it decreases with increasing pressure and decreasing magnetic field.