Function alfven_speed_kernel 

pub fn alfven_speed_kernel(
    b_field: &PhysicalField,
    density: &Density,
    permeability: f64,
) -> Result<AlfvenSpeed, PhysicsError>

Calculates the characteristic speed of Alfven waves. $$ v_A = \frac{B}{\sqrt{\mu_0 \rho}} $$

Arguments

• b_field - Magnetic field $B$ (Uses magnitude $|B|$).
• density - Plasma density $\rho$.
• permeability - Magnetic permeability $\mu_0$.

Returns

• Result<AlfvenSpeed, PhysicsError> - Alfven speed $v_A$.