Pulse modulation provides a new way to tailor the electron density, electron energy and gas temperature in atmospheric radio-frequency（rf） discharges. In this paper, by increasing the rf frequency to several hundred...Pulse modulation provides a new way to tailor the electron density, electron energy and gas temperature in atmospheric radio-frequency（rf） discharges. In this paper, by increasing the rf frequency to several hundreds of MHz, or even much higher to the range of GHz, a very strong peak current in the first period（PCFP） with much larger electron energy can be formed during the power-on phase, which is not observed in the common pulse modulation discharges at a rf frequency of 13.56 MHz. The PIC-MCC model is explored to unveil the generation mechanism of PCFP, and based on the simulation data a larger voltage increasing rate over a quarter of a period and the distribution of electron density just before the power-on phase are believed to play key roles; the PCFP is usually produced in the microplasma regime driven by the pulsed power supply. The effects of duty cycle and pulse modulation frequency on the evolution of PCFP are also discussed from the computational data. Therefore, the duty cycle and pulse modulation frequency can be used to optimize the generation of PCFP and high-energy electrons.展开更多
study drifting modulation instability(MI)that exhibits asymmetric discrete spectrum recurrences in the nonlinear stage within the framework of the focusing nonlinear Schr¨odinger equation.We demonstrate that such...study drifting modulation instability(MI)that exhibits asymmetric discrete spectrum recurrences in the nonlinear stage within the framework of the focusing nonlinear Schr¨odinger equation.We demonstrate that such drifting MI can arise either from the local periodization of general breathers or from numerical simulations starting with an initial modulation containing asymmetric sidebands.展开更多
基金supported by National Natural Science Foundation of China(Grant Nos.11375107 and 11675095)the Fundamental Research Funds of Shandong University(Grant No.2015JC050)
文摘Pulse modulation provides a new way to tailor the electron density, electron energy and gas temperature in atmospheric radio-frequency（rf） discharges. In this paper, by increasing the rf frequency to several hundreds of MHz, or even much higher to the range of GHz, a very strong peak current in the first period（PCFP） with much larger electron energy can be formed during the power-on phase, which is not observed in the common pulse modulation discharges at a rf frequency of 13.56 MHz. The PIC-MCC model is explored to unveil the generation mechanism of PCFP, and based on the simulation data a larger voltage increasing rate over a quarter of a period and the distribution of electron density just before the power-on phase are believed to play key roles; the PCFP is usually produced in the microplasma regime driven by the pulsed power supply. The effects of duty cycle and pulse modulation frequency on the evolution of PCFP are also discussed from the computational data. Therefore, the duty cycle and pulse modulation frequency can be used to optimize the generation of PCFP and high-energy electrons.
基金work was supported by the NSFC(Grant Nos.12522501 and 12247103)the Sci-entific Research Innovation Capability Support Project for Young Faculty(Grant No.SRICSPYF-BS2025131).
文摘study drifting modulation instability(MI)that exhibits asymmetric discrete spectrum recurrences in the nonlinear stage within the framework of the focusing nonlinear Schr¨odinger equation.We demonstrate that such drifting MI can arise either from the local periodization of general breathers or from numerical simulations starting with an initial modulation containing asymmetric sidebands.
