Arc discharge is characterised by

Arc discharge is characterized by a high current passing through a gas which results in a plasma, or ionized gas. This process is initiated by a potential difference, or voltage, existing between two electrodes. This voltage causes the gas in between the electrodes to ionize, creating a pathway for current to flow.

Here are the steps that characterize arc discharge:

1. Initiation: A potential difference is established between two electrodes. This can be done by connecting the electrodes to a power source.

2. Ionization: The potential difference causes the gas in between the electrodes to ionize. This means that the atoms in the gas lose or gain electrons, becoming charged particles. This ionized gas is also known as plasma.

3. Current Flow: The ionized gas provides a pathway for current to flow from one electrode to the other. This current is what we refer to as an arc.

4. Sustenance: The arc can be sustained as long as the potential difference is maintained and there is enough ionized gas to provide a pathway for the current.

5. Termination: The arc is terminated when the potential difference is removed or when the gas is no longer ionized.

In summary, arc discharge is characterized by the ionization of gas due to a potential difference, which allows for a high current to flow between two electrodes.