We present a study of magnetic transport and radiation properties during compression of a magnetized laboratory plasma.A theta pinch is used to produce a magnetized plasma column undergoing radial implosion,with plasm...We present a study of magnetic transport and radiation properties during compression of a magnetized laboratory plasma.A theta pinch is used to produce a magnetized plasma column undergoing radial implosion,with plasma parameters comprehensively measured through diverse diagnostic techniques.High-resolution observations show the implosion progressing through three stages:compression,expansion,and recompression.An anomalous demagnetization phenomenon is observed during the first compression stage,wherein the magnetic field at the plasma center is depleted as the density increases.We reveal the demagnetization mechanism and formulate a straightforward criterion for determining its occurrence,through analysis based on extended-magnetohydrodynamics theory and a generalized Ohm’s law.Additionally,we quantitatively evaluate the radiation losses and magnetic field variations during the two compression stages,providing experimental evidence that magnetic transport can influence the radiation properties by altering the plasma hydrodynamics.Furthermore,extrapolated results using our findings reveal direct relevance to magnetized inertial confinement fusion,space,and astrophysical plasma scenarios.展开更多
The electrochemical carbon dioxide reduction(eCO_(2)RR)to formate,driven by clean energy,is a promising approach for producing renewable chemicals and high-value fuels.Despite its potential,further development faces c...The electrochemical carbon dioxide reduction(eCO_(2)RR)to formate,driven by clean energy,is a promising approach for producing renewable chemicals and high-value fuels.Despite its potential,further development faces challenges due to limitations in electrocatalytic activity and durability,especially for nonnoble metal-based catalysts.Here,naturally abundant bismuth-based nanosheets that can effectively drive CO_(2)-to-formate electrocatalytic reduction are prepared using the plasma-activated Bi_(2)Se_(3) followed by a reduction process.Thus-obtained plasma-activated Bi nanosheets(P-BiNS)feature ultrathin structures and high surface areas.Such nanostructures ensure the P-BiNS with outstanding eCO_(2)RR catalytic performance,highlighted by the current density of over 80 mA cm^(-2) and a formate Faradic efficiency of>90%.Furthermore,P-BiNS catalysts demonstrate excellent durability and stability without deactivation following over 50h of operation.The selectivity for formate production is also studied by density functional theory(DFT)calculations,validating the importance and efficacy of the stabilization of intermediates(^(*)OCHO)on the P-BiNS surfaces.This study provides a facile plasma-assisted approach for developing high-performance and low-cost electrocatalysts.展开更多
基金the State Key Development Program for Basic Research of China(Grant No.2022YFA1602503)the National Natural Science Foundation of China(Grant Nos.12120101005 and 12205247)
文摘We present a study of magnetic transport and radiation properties during compression of a magnetized laboratory plasma.A theta pinch is used to produce a magnetized plasma column undergoing radial implosion,with plasma parameters comprehensively measured through diverse diagnostic techniques.High-resolution observations show the implosion progressing through three stages:compression,expansion,and recompression.An anomalous demagnetization phenomenon is observed during the first compression stage,wherein the magnetic field at the plasma center is depleted as the density increases.We reveal the demagnetization mechanism and formulate a straightforward criterion for determining its occurrence,through analysis based on extended-magnetohydrodynamics theory and a generalized Ohm’s law.Additionally,we quantitatively evaluate the radiation losses and magnetic field variations during the two compression stages,providing experimental evidence that magnetic transport can influence the radiation properties by altering the plasma hydrodynamics.Furthermore,extrapolated results using our findings reveal direct relevance to magnetized inertial confinement fusion,space,and astrophysical plasma scenarios.
基金partial support from the Jiujiang Research Institute at Xiamen University.
文摘The electrochemical carbon dioxide reduction(eCO_(2)RR)to formate,driven by clean energy,is a promising approach for producing renewable chemicals and high-value fuels.Despite its potential,further development faces challenges due to limitations in electrocatalytic activity and durability,especially for nonnoble metal-based catalysts.Here,naturally abundant bismuth-based nanosheets that can effectively drive CO_(2)-to-formate electrocatalytic reduction are prepared using the plasma-activated Bi_(2)Se_(3) followed by a reduction process.Thus-obtained plasma-activated Bi nanosheets(P-BiNS)feature ultrathin structures and high surface areas.Such nanostructures ensure the P-BiNS with outstanding eCO_(2)RR catalytic performance,highlighted by the current density of over 80 mA cm^(-2) and a formate Faradic efficiency of>90%.Furthermore,P-BiNS catalysts demonstrate excellent durability and stability without deactivation following over 50h of operation.The selectivity for formate production is also studied by density functional theory(DFT)calculations,validating the importance and efficacy of the stabilization of intermediates(^(*)OCHO)on the P-BiNS surfaces.This study provides a facile plasma-assisted approach for developing high-performance and low-cost electrocatalysts.
