Study on the influence of temperature on positive streamer under sub-atmospheric pressure

Abstract Electrified transportations are playing more important role during the sustainable development of society, while much more complex environment, such as gas discharge in high altitude, should be considered for the outdoor high voltage insulation safety. The ambient air pressure and temperature are both recognized as significant factors in the streamer dynamics. Herein we established a 2D fluid plasma chemical model with a 5 mm rod-plate gap to explore streamer propagation in air at 50 kPa, 233–353 K. Under sub-atmospheric pressure, temperature increases from 233 K to 353 K accelerate charged particle movement, enhancing streamer velocity and radius. Meanwhile, temperature affects the ionization process. Rising temperature increases electron density in the streamer channel but reduces electric field strength at the streamer head. This study systematically investigates how electron transport coefficients, mean electron energy, space charge and effective ionization coefficients influence streamer discharge. It is observed that, in contrast to atmospheric pressure, the evolution of space charge shows an inverse trend, showing reduced space charge with rising temperature. These findings enhance understanding of sub-atmospheric streamer behavior and establish theoretical foundations for evaluating high-altitude high-voltage system insulation.