  The Micro-Pattern Gaseous Detectors (MPGD) have been widely adopted in
nuclear and particle physics experiments, for their fast response and other
excellent characteristics. To achieve the required signal strength and
detection efficiency, sometimes they are operated at a high voltage range. This
often challenges the limit of high voltage stability of the detector. Discharge
in gaseous detectors is a complex process and involves several responsible
factors. The microscopic geometrical structures of the MPGDs may itself
sometimes induce discharges.
  In this study, we are numerically investigating the discharge phenomena in
non-resistive Micromegas. Within the COMSOL framework, a 3-dimensional model is
developed to observe the occurrence and the development of discharge in
Micromegas. The effect of space charge has been taken into account in the
calculation. The model allows to vary the geometrical parameters of the
detector as well as to study the effects of gas impurities and a different
number of primary charges.
