# Numerical Analysis of the Breakdown Process of CF\({}_{3}\)I at Low Pressure
## 3 Results
### Electron Kinetics
At this stage, the cathode sheath contains more positive than negative charges, resulting in a positive net charge, while the bulk region maintains electrical neutrality with an equal distribution of positive and negative charges. The electric field originating from the unequal charge distribution decelerates electrons, leading to lower electron energies within the bulk region. In contrast, in the cathode sheath, the electric field significantly intensifies due to the reduced distance despite the nearly identical potential difference, thus accelerating electrons to higher energies within the cathode sheath. Abnormally high energy electrons with energies exceeding 250 eV or more are observed in the cathode sheath, while in the bulk region, the electron energy remains below 20 eV. The absolute values of the electron current density within the bulk region reach 1.75 Am\({}^{-2}\), while within the cathode sheath, the values range between 0.25 Am\({}^{-2}\) and 1.5 Am\({}^{-2}\), with higher densities closer to the bulk region. Notably, the electron energy within the cathode sheath experiences significant enhancement during the breakdown stage, while the electron current density does not increase proportionately. Regarding the electron heating rate, the heating rate within the bulk region remains very low, approximately 1 kWm\({}^{-3}\) or less, due to the shielding of the electric field. In contrast, the heating rate within the cathode sheath is markedly high, generally exceeding 20 kWm\({}^{-3}\), attributed to the strong electric field within the sheath. The 15-90 us time period corresponds to the phase of formation of the anode sheath in the after-breakdown stage when a stable cathode sheath has formed. The thickness of the cathode sheath is about 0.8 cm. After 90 us, which corresponds to the stable phase of the after-decomposition stage, a stable anode sheath has formed, and the thickness of the anode sheath is approximately 0.3 cm. In comparison, it is found that the anode sheath is much thinner than the cathode sheath. As the stable sheath has been formed, the electric field in the bulk region is shielded, so that the electron energy in the bulk region will gradually decrease, and when the electron energy decreases to a certain low value, the adsorption reaction will dominate over the ionization reaction, and thus the electron density will gradually decrease. As shown in Figure 4a, the density of electrons in the cathode sheath is 10\({}^{11}\) m\({}^{-3}\) and in the bulk region it is 10\({}^{13}\) m\({}^{-3}\), and the density in the anode sheath is similar to that of the cathode sheath and is also about 10\({}^{11}\) m\({}^{-3}\). The general average density is 10\({}^{12}\) m\({}^{-3}\), which has been significantly reduced compared to the overall average density of 10\({}^{13}\) m\({}^{-3}\) at 15 us. As shown in Figure 4c, the electrons gained greater energy in the cathode sheath and the anode sheath, respectively. The electron energy of the anode sheath is about 20 eV and that of the cathode sheath is about 50 eV. The electron energy in the bulk region is very small. As shown in Figure 4d, the electron heating rate of the cathode sheath is about 20 kWm\({}^{-3}\), the anode sheath is 7 kWm\({}^{-3}\), and the heating rate of the bulk region is basically kept at a low value of less than 1 kWm\({}^{-3}\).