Magnetic field for thin plasma column confinement

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SUMMARY

The discussion centers on the optimal magnetic field strength for confining fully ionized hydrogen plasma within a thin copper tube of 4.4mm inner diameter in an ionizer plasma cannon. A magnetic field strength of approximately 0.2 teslas is proposed to prevent ions from contacting the walls. The conversation highlights the importance of understanding the relationship between ion density, temperature, and magnetic field strength, referencing the formula for pressure given by $$P=\frac{B^2}{2\mu_0}$$, with a practical recommendation to increase the calculated value by a factor of five. Additionally, the use of an RF antenna at 2.4GHz for heating the hydrogen and a DC potential between the antenna and grid is discussed as a method to enhance ion throughput.

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  • Understanding of plasma physics and confinement techniques
  • Familiarity with magnetic field calculations and their effects on charged particles
  • Knowledge of RF heating methods and their application in plasma generation
  • Experience with vacuum systems and pressure measurements in the range of 0.1-2 pascals
NEXT STEPS
  • Research the effects of magnetic confinement on ion behavior in plasma systems
  • Study the principles of RF heating and its impact on ionization efficiency
  • Explore advanced plasma confinement techniques and their practical applications
  • Investigate the mathematical modeling of ion escape rates as a function of density and temperature
USEFUL FOR

Researchers and engineers working in plasma physics, particularly those involved in ionization processes, magnetic confinement systems, and high-throughput ion gun design.

Javier Lopez
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I have a thin copper tube of 4.4mm inner diameter (inside a long ionizer plasma cannon) and I want to fill in with hydrogen plasma fully ionized at low temperature (100eV), what is recommended magnetic field to have the ions there without touching tha walls?
The plasma life is about 0.5 seconds
 
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You clearly have a piece of instrumentation you don't understand. Posting many messages, each with one tiny aspect of the problem but none that give the whole picture is probably not going to be helpful.
 
I need a high throughput ion gun as part of the system. I have more troubles, as the magnetic field needed to maintain the protons frar of the container. My idea is to have about 0.2 teslas. It should help having the formula of how many ions would scape as a function of density, ion temperature, percentage of + ions and magnetic field, if not I will try to obtain it and place here.

Here is one of the ideas I could try. The grid is submitted to AC to increase the throughput. In red there is an RF antenna at 2.4GHz to heat the H2 to more than 10 eV. There is also a DC between antenna and grid that I not draw. (I have to isolate part of the tube at right of the grid but PTFE does not work well with H2 or protons):

zuo9yu.png


In theory the pressure is given by $$P=\frac{B^2}{2\mu_0}$$
But in practice it is recommended to increase 5 times. There is a calculus of the confinement time here:
https://www.researchgate.net/publication/326232448_Useful_formula_and_excel_tables_for_plasma_physics_V07
Formula number 340.

I have about 0.1-2 pascals of H2 but after ionizing and increasing the temperature the pressure is increased also.
 

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