The measurement of plasma density profile in GDT using diagnostic injectorDINA-5.

The diagnostic based on neutral beam injector DINA-5 is developed for the p lasma density measurements at midplane of Gas Dynamic Trap (GDT(1)) experim ent. The deuterium neutral beam with energy of 25 keV and equivalent curren t of up to 2 A is, injected perpendicularly to plasma column at the midplan e of the device. The beam is attenuated by 2-3 times passing through the pl asma. The generated ions are deflected by the magnetic field and registered by a detector array located between the plasma and first wall. The deuteri um ions produced in various points along the initial beam trajectory are de tected in different channels. The signal in each detector depends on the lo cal plasma density in corresponding point enabling to reconstruct the plasm a density profile along the beam. In the experiments with the powerful neut ral beam injection the plasma diamagnetism achieves considerable value (bet a similar to 20%) therefore it has to be taken into account for the accurat e calculation of the D+ trajectories. The space resolution of the method wa s estimated to be about 2 cm. The duration of the beam (up to 4 ms) is larg e enough to overlap the duration of the GDT shots.