**6. Components of Hall thrusters**

There are several ingredients that are responsible for the proper running of a Hall thruster. Below we discuss some important ingredients.

## **6.1 Propellant**

Most of thrusters use xenon as a propellant because of its higher mass (131.3 amu), lower first ionization potential, less toxicity, ionization cross section of 2.3 <sup>10</sup><sup>6</sup> cm<sup>2</sup> . Unfortunately, Xenon is very expensive (compared to Krypton high value of first ionization potential) because of its mere availability at the earth's atmosphere [20].

### **6.2 Anode and cathode**

Latest thrusters have hollow anodes through which the propellant is pumped into a closed channel. The propellant Xenon is stored in a tank on the spacecraft and reaches the anode. Hollow cathodes are used in Hall thruster to provide electrons (with the help of DC electron-discharge plasma generator) to neutralize the body of the spacecraft (to manage spacecraft charging) as well to sustain the plasma discharge and. The hollow cathode are made up with refractory metal tube and lanthanum hexaboride [1–20]. The cathode operates at 30 V to 40 V negative of the anode in a mercury thruster depending on the design consideration.
