As soon as a free electron appears in the gas, it is accelerated under the action of an electric field, its kinetic energy increases, and if the condition eEl> A (u) is satisfied, then it ionizes it when it collides with a molecule. The primary and secondary electrons are accelerated again, and each of them knocks out one more electron, etc.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.