For 10 points, identify the fourth state of matter that is a cohesive, partially ionized collection of matter, exemplars of which include flames and sparks.
When a magnetic field is present, Alfvén waves are found in it at frequencies less than the ion cyclotron frequency. It may be technically defined as a system that experiences Debye [deh-BYE] self-shielding, and the properties of one with a kinetic temperature on the order of 10 keV [kiloelectronvolts] or less may be measured with a Langmuir probe. For 10 points, identify the fourth state of matter that is a cohesive, partially ionized collection of matter, exemplars of which include flames and sparks.
When a magnetic field is present, Alfvén waves are found in it at frequencies less than the ion cyclotron frequency.
{plasma}