The Bennett Pinch
Plate 079 Physics Poster
Plate 79 speaks for itself: “Current that strangles itself.”
The Physics
A current along a plasma column makes a magnetic field that squeezes it inward. In equilibrium the magnetic pressure balances the plasma's thermal pressure.
μ₀ I² = 8π N k_B (T_e + T_i)
- μ₀: vacuum permeability, N A⁻²
- I: current, A
- N: particles per unit length, m⁻¹
- k_B: Boltzmann constant, J K⁻¹
- T_e, T_i: electron and ion temperatures, K
Its own magnetic field squeezes the plasma. Bennett, 1934.
Sources
- W. H. Bennett, Phys. Rev. 45, 890 (1934).
On the poster
Plate 079, “The Bennett Pinch”: the pixel-art plate with its slogan “Current that strangles itself.”, the key equation and the facts panel shown above. Pixelated Physics. Physics. Personified.
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