One of the problems specifying erosion of the cathode is to establish the conditions giving rise to a diffuse or contracted arc-cathode interaction independent of its type and construction. In various works transition...One of the problems specifying erosion of the cathode is to establish the conditions giving rise to a diffuse or contracted arc-cathode interaction independent of its type and construction. In various works transition from one interaction mode to another was related to the value of a critical current, a pressure range etc. A criterion related to a thermal state of the cathode has greater generality, since it essentially varies with the arc-cathode contacts. First of all it relates to emission cooling relationship with the other components of the cathode heat flux. It is established that in the contracted sport the emission cooling exceeds the radiation one by a factor of 50 to 100. For a diffuse contact the emission and radiation components of the cathode heat loss become comparable. A cathode thermal state is the effect of the arc confined head load. Under these conditions temperature in the arc-cathode contact area depends on the geometrical dimensions of the electrode. The effect of electrode thickness on temperature is indefinite and depends on the thermophysical properties of the electrode, i.e. thermal conductance and its surface blackness.展开更多
文摘One of the problems specifying erosion of the cathode is to establish the conditions giving rise to a diffuse or contracted arc-cathode interaction independent of its type and construction. In various works transition from one interaction mode to another was related to the value of a critical current, a pressure range etc. A criterion related to a thermal state of the cathode has greater generality, since it essentially varies with the arc-cathode contacts. First of all it relates to emission cooling relationship with the other components of the cathode heat flux. It is established that in the contracted sport the emission cooling exceeds the radiation one by a factor of 50 to 100. For a diffuse contact the emission and radiation components of the cathode heat loss become comparable. A cathode thermal state is the effect of the arc confined head load. Under these conditions temperature in the arc-cathode contact area depends on the geometrical dimensions of the electrode. The effect of electrode thickness on temperature is indefinite and depends on the thermophysical properties of the electrode, i.e. thermal conductance and its surface blackness.
