Electronegative gases are gases that have a higher electron affinity, which means they have a greater tendency to attract and hold onto electrons. Examples of electronegative gases include chlorine, fluoride, and oxygen.
The breakdown strength, or the electrical field strength required to cause electrical breakdown in a gas, is higher in electronegative gases compared to other gases because the electronegative atoms or molecules in these gases can more readily capture free electrons and form negative ions. This reduces the number of free electrons available for conduction, making it more difficult for an electrical breakdown to occur.
Anode streamers are luminous discharges that occur in electrical breakdown in gases and that originate from the anode, or the positively charged electrode. Cathode streamers are similar discharges that originate from the cathode, or the negatively charged electrode. They are caused by the ionization of the gas and the movement of electrons in the electric field. These streamers are responsible for the initiation of the electrical breakdown.