For highly conductive plasma (conductivity (σ) → ∞), we often say that the plasma is ‘frozen-in’ the magnetic field lines, but what does this mean physically? Let’s begin by examining the mathematical (forgive me) behavior of the flow. From Ohm’s Law and Ampere’s Law1 Solve for E Take the curl of both sides By Faraday’s Law and the vector identify for Recall the Maxwell equation that says that there can be no magnetic monopoles and distribute the negative sign where…
If the sun didn’t rotate, then the frozen-in magnetic field would be carried out radially with the solar wind (v = 440 km/s on average). Instead, the sun’s rotation (ω = 2.87 x 10-6 rad/s) drags the magnetic field configuration into a Parker Spiral. The angle between the radial flow and the spiral can be found with simple trigonometry. where the radial component of the magnetic field at some distance from the sun’s center can be found through the conservation…
Ion Cyclotron Waves (ICWs) are transverse shear waves produced as energy is released from a higher energy anisotropic distribution of ions (a.k.a. a “ring distribution” in velocity space) to a lower energy isotropic distribution. Specifically, the anisotropy arises when neutrals are ionized and accelerated along the magnetic field. The ICWs will release energy from the plasma and scatter the pick-up ions’ velocity back to thermal equilibrium. Tpar describes the ions’ temperature distribution parallel to the magnetic field and Tperp describes…