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Leo Liu
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I really can't get my head around the concept of pulsed plasma thruster. All I know now is that it utilizes ##\vec F=q \dot {\vec r}\times \vec B##. Could someone explain the mechanism to me, please? Thanks!
A short, hand wavy, description:Leo Liu said:View attachment 290680
I really can't get my head around the concept of pulsed plasma thruster. All I know now is that it utilizes ##\vec F=q \dot {\vec r}\times \vec B##. Could someone explain the mechanism to me, please? Thanks!
Thank you. I understand everything now but what sets the plasma in motion.DaveE said:A short, hand wavy, description:
When the arc forms, hopefully on the right side near the teflon, it creates the B field (out of the page). Then the moving electrons (up) experience the force you described ##\vec F=q \dot {\vec r}\times \vec B## (to the right). So that arc is propelled to the right and pushes a bunch of teflon bits out with it. The arc extinguishes when it's source discharges, and then the cycle repeats.
I like to think that the force is created to oppose a change in the magnetic flux. For a given current amount, the flux can be reduced by increasing the loop area, i.e. pushing the arc away.
This is also how rail guns work, if you want to look into those too.
The arc is initiated across the contaminated surface of the PTFE. There is no atmosphere. The arc forms a high temperature plasma of PTFE breakdown products.Leo Liu said:but what sets the plasma in motion.
Also collisions with the outward moving electrons will push some of the plasma. The charged ions will also feel E and B field forces, like the electrons.Leo Liu said:Thank you. I understand everything now but what sets the plasma in motion.
A pulsed plasma thruster works by creating a plasma, which is a gas that has been heated to extremely high temperatures, and then expelling it out of the back of the thruster at high speeds. This creates a reaction force in the opposite direction, propelling the spacecraft forward.
The fuel source for a pulsed plasma thruster is typically a noble gas, such as xenon or argon. These gases are ionized and heated to create the plasma used for propulsion.
A pulsed plasma thruster differs from other types of thrusters in that it uses a pulsed discharge to create the plasma, rather than a continuous discharge. This allows for more efficient use of the fuel and a higher specific impulse, or thrust per unit of fuel.
Some advantages of using a pulsed plasma thruster include its high specific impulse, which allows for longer missions and more efficient use of fuel. It also has a low mass and can operate for long periods of time without needing to be refueled.
One limitation of a pulsed plasma thruster is its low thrust compared to other types of thrusters, which limits its use for larger spacecraft. It also requires a significant amount of power to operate, which can be a challenge for smaller spacecraft. Additionally, the plasma can erode the thruster over time, requiring maintenance or replacement.