Effect of Ambient Electrons on Primary Discharge Energy in Laser-Induced Discharge

We examined the laser-induced discharge (LID) in medium-vacuum air. The time-averaged discharge energy W
_d
of a primary discharge prior to an arc discharge was affected by the number of initial electrons. The initial electrons were produced by the laser irradiation of electrodes. The number of electrons was proportional to the energy of the laser, L
_p
. Thus, it was adjusted by changing L
_p
. Although the experimental conditions were rather limited, i.e., air at 200-Pa pressure, we demonstrated a simple relationship, W
_d
∝ V
_s
²
× L
_p
^s
, where Vs is the applied voltage and s is an exponent determined empirically. Note that the number of initial electrons is a function of L
_p
. Such a simple relationship for the behavior of LID that incorporates W
_d
is proposed for the first time in this paper.