Liner

Liner is term used for central toroid of the chamber which contains plasma column. Liner of tokamak GOLEM is of classical toroidal shape with circular cross section. Main radius od the liner is 0.4 m and minor radius is equal to 0.1 m. This determines tokamak GOLEM to be tokamak of small class and large aspect ratio. The original liner from when this tokamak was named TM-1 was replaced in 1984, however its dimensions did not change. A sample of the replaced liner can be seen in fig. 1.

Inside of the liner


A diagnostic port

As can be seen in fig. 1, liner is made of bellows stainless steel, which is standard material in vacuum technology. There are 6x3 ports present in current liner. Since the liner has circular cross section, plasma boundary is defined by a circular material limiter made of molybdenum. Having radius of 0.085 m, it is placed inside of liner to hinder interaction of plasma with the wall of chamber.

As was mentioned already, for tokamak to be operational, a high level of vacuum is necessary to be present inside its innermost layer of chamber (e.g. liner). Inside of GOLEM, background pressure of vacuum is usually maintained on values of 10 - 200 mPa. In order to enhance the vacuum exhaustion, the liner is baked, which means that it is possible to raise its temperature to 300 Celsius degrees. It is therefore necessary for all the tokamak components placed inside of liner to be constructed in a way to withstand such temperatures.