Ionization in the circuit breaker is facilitated by
The ionization in a circuit breaker is facilitated by high temperature, the increase of mean free path, and increasing field strength.
When the voltage across the contacts of a circuit breaker is high enough, it can cause the air or gas surrounding the contacts to become ionized.
The ionization process creates a plasma that can conduct current, allowing the current to continue to flow even after the contacts have physically separated.
High temperature can increase the rate of ionization by providing the air or gas molecules with additional energy to undergo ionization. Increasing the mean free path, or the average distance between molecules, can reduce the likelihood of collisions that would prevent ionization from occurring.
Increasing the field strength can directly ionize the air or gas molecules and create a conductive path between the contacts.