Influence of Microscopic Electric Field Enhancement on Microparticle Impact Phenomena Based on Fractal Modeling

The objective of this paper is to study the influence of microscopic electric field enhancement caused by microprotrusions on microparticle impact phenomena based on fractal modeling. In this paper, microprotrusions with a radius of 5 μm and heights 0, 1, 2, 5, and 10 μm are considered, according to the height-width ratios 0, 0.2, 0.4, 1, and 2, respectively. The microparticles and contacts are assumed to be made of copper. The radius of the microparticle is assumed to be 0.1 μm and the applied voltage is 60 kV. First, microprotrusions with different height-width ratios are modeled based on fractal theory. Then, the microscopic electric field distortions caused by microprotrusions on the contact surface are simulated based on fractal models of microprotrusions. The impact velocities of microparticles under different cases are calculated based on basic microparticle theories. Finally, the microparticle impact phenomena are simulated using the smoothed particle hydrodynamics method under the microscopic electric field caused by microprotrusions on the contact surface. The results show that the microscopic electric field enhancement caused by microprotrusions will have a significant influence on impact velocities, the characteristics of secondary particles, and the craters produced on the target contact surface. The results of this paper may provide some useful information to further understand the vacuum breakdown initiated by microparticles.