Method for controlling plasma edge fuel particle backflow by powder feedback injection

A method for controlling plasma edge fuel particle backflow by powder feedback injection using a system, the system comprising a fusion device, a visible spectrum diagnostic system, a plasma control system, a wall, an amplitude mapping converter and a lithium powder injection system;

• the fusion device being a magnetically confined fusion reaction device;
• the visible spectrum diagnostic system including reflectors on a upper part and a lower part of a horizontal window of the fusion device;
• the plasma control system including a control algorithm configured to implement feedback control on a plasma based on acquired parameter diagnostic information of the plasma;
• the wall being a chamber wall facing the plasma in the fusion device, the amplitude mapping converter configured to convert an output voltage signal of the plasma control system into a sine wave signal;
• the lithium powder injection system being arranged at a top of the fusion device, and configured to inject lithium powder into the fusion device after receiving an output signal of the amplitude mapping converter;
• the lithium powder injection system being successively connected to the amplitude mapping converter, the plasma control system and the visible spectrum diagnostic system;
• the method comprising:
• setting a start time and an end time for control algorithm execution in the plasma control system;
• after the setting the start time and the end time, generating and maintaining, by the fusion device, a plasma discharge;
• during the plasma discharge, measuring a Da value of Da line emission in real-time by the visible spectrum diagnostic system, the Da value being measured as an intensity of the the Da line emission at upper and lower divertor regions of the fusion device and at part of the an inner wall of the wall, the Da value reflecting a level of fuel recycling during an interaction between the plasma and the wall, the Da line emission being radiation emitted by deuterium atoms upon transition from an excited state and indiucating an edge fuel particle level of the plasma;
• filtering, by the plasma control system, the measured Da value by a low-pass filter, and comparing the measured Da value with a set target Da value;
• when the measured Da value is greater than the set target Da value, calculating an output voltage value of the output voltage of the plasma control system according to an PID algorithm formula of the control algorithm, the output voltage value being positively related to a difference value between the measured Da value and the set target Da value, wherein the output voltage value ultimately determines a magnitude of a flow rate of the lithium powder injected into the fusion device, the PID algorithm formula being
• Y
• (
• t
• )
• =
• k
• p
• ⁢
• E
• ⁡
• (
• t
• )
• +
• k
• i
• ⁢
• ∫
• 0
• t
• E
• ⁡
• (
• t
• )
• ⁢
• dt
• +
• k
• d
• ⁢
• dE
• ⁡
• (
• t
• )
• dt
• ,
• wherein E(t)=Dα_set−Dα(t), wherein Dα_set represents a set target value Da, and Dα(t) represents a value of Da at a moment t;
• kp, ki, kd are a proportion, an integral and a difference parameter, respectively, and Y(τ) is an output voltage value;
• when the measured Da value is less than or equal to the set target Da value, determining the output voltage value to be 0;
• converting, by the amplitude mapping converter, the output voltage of the plasma control system into the sine wave signal with an amplitude value being a magnitude of the output voltage value and with a frequency, and outputting the sine wave signal to the lithium powder injection system;
• and
• injecting, by the lithium powder injection system, lithium powder into the fusion device based on the sine wave signal, wherein the lithium powder injected into the fusion device adsorbs fuel particles generated by the interaction between the plasma and the wall, so that backflow of the fuel particles is reduced, and the Da line emission intensity is also reduced.