A kinetic simulation model has been employed to study the properties of an electronegative magnetized plasma sheath assuming the cut-off distribution of electrons and negative ions.The fundamental kinetic Bohm conditi...A kinetic simulation model has been employed to study the properties of an electronegative magnetized plasma sheath assuming the cut-off distribution of electrons and negative ions.The fundamental kinetic Bohm condition for the electronegative magnetized plasma has paramount importance for the formation of a stationary plasma sheath near the material wall.The presence of an oblique magnetic field in an electronegative plasma affects the ion distribution at the plasma injection side and at the wall.The temperature profile of negative charged particles has a non-uniform distribution,which determines the energy flow towards the wall.展开更多
Kinetic theory has been employed to investigate the magnetized plasma-sheath structure and its characteristics in the presence of more than one species of negatively charged particles:hot electrons,cold electrons,and ...Kinetic theory has been employed to investigate the magnetized plasma-sheath structure and its characteristics in the presence of more than one species of negatively charged particles:hot electrons,cold electrons,and negative ions.The cold electrons and negative ions are considered to obey a Maxwellian distribution,whereas the hot electrons follow a truncated Maxwellian distribution.The Bohm sheath condition has been extended for the case of more than one species of negatively charged particles,in which the concentration of hot electrons has a crucial role in achieving the Bohm velocity.The thermal motion of hot electrons is much higher compared to cold electrons and negative ions,such that the variation of hot electron concentrations and the temperature ratio of hot to cold electrons play a key role in the determination of the plasma-sheath parameters:particle densities,electrostatic potential,the flow of positive ions towards the wall,and sheath thickness.We have estimated the deviation of the resultant drift velocity of positive ions on the plane perpendicular to the wall from the parallel component at the presheath–sheath interface.It is found that the deviation between the two velocity components increases with an increase in the obliqueness of the magnetic field.Furthermore,the results obtained from the kinetic trajectory simulation model are compared with the results obtained using a fluid model;the results are qualitatively similar,although the potential varies by less than 4%in terms of the magnitude at the wall.展开更多
In this work, we construct electrodes of brass to produce plasma by arc discharge and is characterized by using a movableLangmuir single probe. It is a simple way to measure plasma parameters such as electron temperat...In this work, we construct electrodes of brass to produce plasma by arc discharge and is characterized by using a movableLangmuir single probe. It is a simple way to measure plasma parameters such as electron temperature, electron density and iondensity. A movable Langmuir single probe technique has a reference point since it is biased with reference to any one electrode ofthe plasma producing system. The values obtained are at atmospheric pressure. The plasma thus produced in laboratory has variousapplications which include gaseous discharge, plasma torch, sputtering, laser produced plasma as well as tokamak plasma.展开更多
基金Suresh Basnet would like to acknowledge the University Grants Commission,Nepal for the PhD fellowship.
文摘A kinetic simulation model has been employed to study the properties of an electronegative magnetized plasma sheath assuming the cut-off distribution of electrons and negative ions.The fundamental kinetic Bohm condition for the electronegative magnetized plasma has paramount importance for the formation of a stationary plasma sheath near the material wall.The presence of an oblique magnetic field in an electronegative plasma affects the ion distribution at the plasma injection side and at the wall.The temperature profile of negative charged particles has a non-uniform distribution,which determines the energy flow towards the wall.
基金the University Grants Commission,Nepal for the PhD fellowship Ph D/075-76S&T-16。
文摘Kinetic theory has been employed to investigate the magnetized plasma-sheath structure and its characteristics in the presence of more than one species of negatively charged particles:hot electrons,cold electrons,and negative ions.The cold electrons and negative ions are considered to obey a Maxwellian distribution,whereas the hot electrons follow a truncated Maxwellian distribution.The Bohm sheath condition has been extended for the case of more than one species of negatively charged particles,in which the concentration of hot electrons has a crucial role in achieving the Bohm velocity.The thermal motion of hot electrons is much higher compared to cold electrons and negative ions,such that the variation of hot electron concentrations and the temperature ratio of hot to cold electrons play a key role in the determination of the plasma-sheath parameters:particle densities,electrostatic potential,the flow of positive ions towards the wall,and sheath thickness.We have estimated the deviation of the resultant drift velocity of positive ions on the plane perpendicular to the wall from the parallel component at the presheath–sheath interface.It is found that the deviation between the two velocity components increases with an increase in the obliqueness of the magnetic field.Furthermore,the results obtained from the kinetic trajectory simulation model are compared with the results obtained using a fluid model;the results are qualitatively similar,although the potential varies by less than 4%in terms of the magnitude at the wall.
文摘In this work, we construct electrodes of brass to produce plasma by arc discharge and is characterized by using a movableLangmuir single probe. It is a simple way to measure plasma parameters such as electron temperature, electron density and iondensity. A movable Langmuir single probe technique has a reference point since it is biased with reference to any one electrode ofthe plasma producing system. The values obtained are at atmospheric pressure. The plasma thus produced in laboratory has variousapplications which include gaseous discharge, plasma torch, sputtering, laser produced plasma as well as tokamak plasma.
