A worldwide effort is presently being invested in the development of small spacecraft, propelled with advanced electric propulsion engines. Among the electric rocket engines that are considered as the candidates for applications on small spacecraft, Hall thrusters (HTs) occupy a prominent place. This is due to the following factor: at moderate and large powers (0.5 – 15 kW), HTs possess the highest efficiency at velocities of plasma, leaving the thruster, of 1.2∙10⁴ – 2.5∙10⁴ m/s, which are optimal nowadays and in the coming decade. However in the case of HTs, operated at powers of 50 – 300 W, as needed to propel small spacecraft, the problem of a compatibility of a high efficiency and an acceptable lifetime arises. It is due to the fact that reducing mass flow rate causes decreasing the rate of ionization and in order to achieve acceptable mass efficiency, it is necessary to reduce sizes of the acceleration channel. This, in turn, leads to a fast fall of the thruster lifetime until unacceptable value. In order to solve the problem, a new concept of low power Hall thruster has been proposed and patented at Asher Space Research Institute (ASRI) of Technion. It has been called CAMILA Hall thruster (CAMILA – Co-Axial Magneto-Isolated Anode). The CAMILA Hall thruster differs from conventional Hall thruster by the significantly more complex topology of magnetic field and new configuration of the anode. Experimental investigations of CAMILA-HT-55, carried out initially at Sorec NRC and last time in the new Electric Propulsion Laboratory of ASRI- Technion, showed that, with taking into account the large evaluated lifetime of the model, the performance of CAMILA HT-55 is the best in the power range of 120 – 350 W in comparison with presently available Hall thrusters in the world.

The new structure of the magnetic field lines and the new configuration of anode in the CAMILA Hall thruster bring about very essential difference in physical processes in comparison with conventional Hall thruster. Some features of these processes are considered in presentation. They are:

1. The mechanism of a containment of electrons, which provides the creation of the electric field, directed to a centerline of the anode cavity, and results of theoretical estimation of the needed induction of the longitudinal magnetic field.
2. The potentialities to arise for such plasma instabilities as Rayleigh-Taylor, Gradient, Kelvin- Helmholtz, Lower-Hybrid ones in the anode cavity and their possible role in transfer of the electrons across the magnetic field.

The experimental investigations showed that a rather high efficiency can be obtained even in the simplified version of the CAMILA Hall thruster, where a longitudinal component of the magnetic field in the anode cavity is created with only basic magnet, that is, without using the anode coils. In application to the simplified version of CAMILA Hall thruster, the following points are considered:

1. The general conclusion about processes in the anode cavity (a negative jump of potential near inner anode, an ionization of atoms by electrons, penetrating into cavity from the acceleration channel, a significant role of mirror effect near outer dielectric wall of the acceleration channel in processes in the anode cavity).
2. The mechanism of a plasma penetration into anode cavity and results of an estimation of a deepness of its penetration.
3. The centrifugal mechanism of electron confinement in the anode cavity.

Besides, the results of the experimental investigations of low-frequency oscillations in simplified and full versions of CAMILA Hall thruster are presented.