The experimental results in the GAMMA10 tandem mirror have demonstrated the improvement of the axial plasma confinement. As it makes progress the radial loss can't be getting neglected.
GAMMA10 is essentially designed as the axi-symmetrized tandem mirror. In the axial symmetric magnetic field, the particles experience small radial drift locally, but it it canceled through the bounce motion. Consequently particles passing through the mid-plane in the GAMMA10 central cell are not expected to drift for a radial direction. However GAMMA10 is consist of not only central mirror cell but other mirror cells. Especially there are mirror cells called transition mirror cell, the magnetic field is not axial symmetry there.The possibility of the radial drift due to the non-axisymmetric magnetic field in the GAMMA10 has already been described.
We calculated numerically particle orbits trapped in the non-axisymmetric magnetic field transition mirror cells in the GAMMA10 to examine the feature of the radial drift. It's found that those orbits are deviated from the magnetic flux tube.
The fact indicates the existence of "radial loss cone" in view of the limiter. The radial drift due to the radial loss cone is examined numerically and analytically.

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