New Research on Plasma Physics Reveals Accuracy Issues with Standard Formula

Strategic Insights -

A recent study published in Physics of Plasmas has shed light on the accuracy of the standard formula for calculating the diamagnetic signal in a tokamak, a device used to confine and study plasmas. Researchers used the SPIDER code to calculate plasma equilibrium in a tokamak with a circular plasma in a wide range of beta(p) and ell(i) (poloidal beta and internal inductance) values. The study found that the detected differences between the calculated and predicted values of the diamagnetic signal were significant and could not be explained by the standard formula.

Key Takeaways:

  • The study used the SPIDER code to calculate plasma equilibrium in a tokamak with a circular plasma in a wide range of beta(p) and ell(i) values.
  • The researchers found that the detected differences between the calculated and predicted values of the diamagnetic signal were significant and could not be explained by the standard formula.
  • The study identified the reasons for the difference and the range of parameters where the accuracy of the formula is insufficient to interpret the data.
  • The loss of accuracy in analytical theory is due to the fact that only linear corrections in the inverse aspect ratio were taken into account when calculating the diamagnetic signal.
  • The study concluded that the standard formula is insufficient to interpret the data in certain parameter ranges, and that more accurate calculations are needed to achieve reliable results.

Statistics:

  • The study used a circular plasma in a wide range of beta(p) and ell(i) values.
  • The detected differences between the calculated and predicted values of the diamagnetic signal were significant, with values exceeding 10% in certain parameter ranges.
  • The study identified the range of parameters where the accuracy of the formula is insufficient to interpret the data as 0.1 < beta(p) < 0.5 and 0.5 < ell(i) < 5.
  • The study found that the loss of accuracy in analytical theory was due to the fact that only linear corrections in the inverse aspect ratio were taken into account when calculating the diamagnetic signal.

Sources:

  • On the Accuracy of the Standard Formula for Diamagnetic Signal In a Tokamak. Physics of Plasmas, 2025;32(9).
  • NewsRx. Findings from Russian Academy of Sciences Broaden Understanding of Plasma Physics (On the Accuracy of the Standard Formula for Diamagnetic Signal In a Tokamak). Journal of Physics Research. October 21, 2025; p 102.