NEED ALL PARTS

NPRE 429 Midterm (Take-home) Prof. Ruzic, Spring 2023 March 8, 2023 Due at the start of class Wednesday March 22,2023 1. Consider a cylindrical plasma with a radius of 3cm and a length of 50cm. The input power is 100W. The pressure is 1.0 Torr of Argon. (a) (25 points) What is the electron temperature in eV ? Get this by balancing loss to the walls with ionization considering only equation 2 on page 81 in L\&L. (b) (25 points) What is the electron density? Get this by using a power balance. Now set up reaction rate equations to determine the amount of Ar(4s) in the plasma using the table on p.81 of L\&L. Note: There is virtually no Ar(4p) in the plasma because its radiative decay (reaction \#14) is so high. There is no radiative decay for Ar(4s) because that metastable state would have to decay from an " s " to an " s " and that transition is "forbidden". The end result is that Ar(4s) actually ends up existing in the plasma. Your balance equation needs to consider making Ar(4s) via reaction 4 , and losing it via reactions 5,8 , and 10 . Of course Ar(4s) is also lost by diffusion to the walls. (c) (5 points) Why do you not need to consider reaction 9 ? Note that the density of Ar+=the electron density since a plasma is quasineutral. The argon ions, argon excited states, and the neutral ground state argon gas atoms are all in thermal equilibrium with each other and with the walls of the container. (d) (25 points) Find the density of Ar(4s) in the plasma. Look at reaction 10 on p.81 L\&L. It is much easier to ionize an Ar(4s) than an Ar ground state atom (reaction 2), yet when you calculated the electron temperature in part (a) you only considered equation \#2. Now that you have an answer to part (d) .... (e) (20 points) Find the electron temperature in eV of the plasma by balancing loss to the walls with all sources of ionization. Compare this answer to your answer from part (a) and comment. If you can not get part (a): Use 1.5eV for the electron temperature to do the rest of the exam. If you can not get part (b): Use 11011cm3 for the electron density for the rest of the exam. If you can not get part (d) : Use 11012cm3 for the Ar(4s) density for the rest of the exam. Special Note: The values above are not the right answers