ИСТИНА

In 1970 Australian physicist R.Boswell [1], investigating the inductive RF discharge, placed in an external magnetic field, discovered a resonant increase of the plasma density at some values of the magnetic field induction. Later F.Chen [2] hypothesized that under experimental conditions of R. Boswell helicons were excited in a discharge whose energy was absorbed by nonlinear collisionless Landau damping mechanism. However later studies [3, 4, 5] showed that the energy is absorbed not primarily due to helicon, but due to the associated Trievelpiece-Gold wave (or oblique Langmuir wave). Best RF power input can be obtained by placing the discharge in an external magnetic field, whose value corresponds to the conditions of resonant excitation of the waves. In [6-8], these statements were analyzed using mathematical modeling and were confirmed experimentally. In the mid-1990s R.Bosvell [9-12] showed that when using a divergent magnetic field ions with energies of several tens of eV were observed. The reason for the acceleration of ions on the hypothesis of R.Boswell is a potential drop that occurs at the boundary of different diameter chambers. In 1995 a group of Australian scientists, led by R.Boswell suggested to use this effect to generate thrust in a new electrodeless ion thruster. The new thruster was named the helicon double layer thruster (HDLT). In present work we provide the results of the modified thruster test. The differences between our model and R.Boswell`s are the following: the first is the constriction between gas discharge and vacuum chambers to create pressure drop was made, the second is the use of much lower RF powers. The latter provides predominant power input through the Treivelpiece Gold channel. Here we present the dependencies between Ion Energy Distribution Function (IEDF) and external parameters – power input, gas consumption and magnetic field value. The investigation showed the presence of accelerated ions with energies up to 160 eV even without the magnetic field. However application of a magnetic field up to the resonant value leads to the increase of ion maximum energy. After violation of resonance conditions ion maximum energy starts to decrease.