**6. Worldwide scenario of gyrotron for plasma heating**

Worldwide, a number of research institutions, academic institutions and industries are working in the field of gyrotron, with frequency varying from lower end of microwave range (8 GHz) to 1 THz. The output power of these gyrotrons also ranges from 100 s of kW to few MW. Pulse duration also varies from few milliseconds to full continuous wave (CW) operation. The efficiency of gyrotron varies from 10–70%. The worldwide scenario of Gyrotron for plasma heating purpose are presented in the **Tables 3** and **4** [7, 11–13, 19–21].

