Analysing ITER parameters¶

Let’s try to look at ITER plasma conditions using the physics subpackage.

from astropy import units as u
from plasmapy import physics
import matplotlib.pyplot as plt
import numpy as np
from mpl_toolkits.mplot3d import Axes3D


The radius of electric field shielding clouds, also known as the Debye length, would be

electron_temperature = 8.8 * u.keV
electron_concentration = 10.1e19 / u.m**3
print(physics.Debye_length(electron_temperature, electron_concentration))


Out:

6.939046841173439e-05 m


Note that we can also neglect the unit for the concentration, as 1/m^3 is the a standard unit for this kind of Quantity:

print(physics.Debye_length(electron_temperature, 10.1e19))


Out:

/home/docs/checkouts/readthedocs.org/user_builds/plasmapy/checkouts/latest/plasmapy/utils/decorators/checks.py:309: UnitsWarning: No units are specified for n_e = 1.01e+20 in Debye_length. Assuming units of 1 / m3.
To silence this warning, explicitly pass in an Astropy Quantity (from astropy.units)
(see http://docs.astropy.org/en/stable/units/)
warnings.warn(UnitsWarning(unit_casting_warning))
6.939046841173439e-05 m


Assuming the magnetic field as 5.3 Teslas (which is the value at the major radius):

B = 5.3 * u.T

print(physics.gyrofrequency(B, particle='e'))



Out:

932174612509.1257 rad / s
/home/docs/checkouts/readthedocs.org/user_builds/plasmapy/checkouts/latest/plasmapy/utils/decorators/checks.py:482: RelativityWarning: thermal_speed is yielding a velocity that is 18.559% of the speed of light. Relativistic effects may be important.
RelativityWarning)
5.968562743414285e-05 m


The electron inertial length would be

print(physics.inertial_length(electron_concentration, particle='e'))


Out:

0.0005287720431268747 m


In these conditions, they should reach thermal velocities of about

print(physics.thermal_speed(T=electron_temperature, particle='e'))


Out:

55637426.625786155 m / s


And the Langmuir wave plasma frequency should be on the order of

print(physics.plasma_frequency(electron_concentration))


Out:

566959736046.5352 rad / s


Let’s try to recreate some plots and get a feel for some of these quantities.

n_e = np.logspace(4, 30, 100) / u.m**3
plt.plot(n_e, physics.plasma_frequency(n_e))
plt.scatter(
electron_concentration,
physics.plasma_frequency(electron_concentration))
plt.xlabel("Electron Concentration (m^-3)")