text: Six root two, times pi to the three halves, over the natural logarithm of the namesake parameter of these systems is used to calculate the Coulomb collision time.
full_question: Six root two, times pi to the three halves, over the natural logarithm of the namesake parameter of these systems is used to calculate the Coulomb collision time. The magnetic diffusivity is used in the Reynolds number for these systems. Filaments in these systems get pinched inward due to external magnetic fields. Although these systems are (*) "quasi-neutral", redistribution of electrons in them forms an electrostatic sheath to screen out electric fields. Toroidal field lines are necessary to confine these substances stably, as in a tokamak. These extremely conductive substances can form when gas is ionized. For 10 points, name this "fourth" state of matter.
first_sentence: Six root two, times pi to the three halves, over the natural logarithm of the namesake parameter of these systems is used to calculate the Coulomb collision time.
raw_answer: plasma [prompt on conductors]