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what are thermal plasmas? - plasmas that have particles that collide in…

Question

what are thermal plasmas?

  • plasmas that have particles that collide infrequently
  • plasmas that do not reach thermal equilibrium
  • plasmas that reach a temperature equal to their surroundings
  • plasmas that have only a few particles ionized at any given moment

Explanation:

Define plasma types

Plasmas are broadly classified into thermal (equilibrium) and non-thermal (non-equilibrium) plasmas based on the relative temperatures of their constituent particles (electrons, ions, and neutral species).

Analyze thermal equilibrium

In Plasma Properties, thermal plasmas are characterized by local thermodynamic equilibrium (LTE). This means that the heavy particles (ions and neutral atoms/molecules) and the light particles (electrons) reach approximately the same temperature due to frequent collisions.

Evaluate the options

  • "plasmas that have particles that collide infrequently": Incorrect, as high collision frequency is required to distribute energy and reach thermal equilibrium.
  • "plasmas that do not reach thermal equilibrium": Incorrect, this describes non-thermal (cold) plasmas.
  • "plasmas that reach a temperature equal to their surroundings": Incorrect, plasmas are typically much hotter than their surrounding ambient environment.
  • "plasmas that have only a few particles ionized at any given moment": Incorrect, this describes weakly ionized (often non-thermal) plasmas.

Note: Since the options provided do not perfectly state "plasmas in thermal equilibrium" but rather contrast with non-equilibrium, let's re-evaluate the standard definition. Thermal plasmas are indeed those where the electrons and heavy particles are in thermal equilibrium with each other. If we look closely at the second option, "plasmas that do not reach thermal equilibrium" is the definition of non-thermal plasmas. Therefore, thermal plasmas are those that do reach thermal equilibrium (the opposite of the second option).

Let's re-read the third option: "plasmas that reach a temperature equal to their surroundings". In some introductory contexts, "surroundings" might refer to the local thermal equilibrium of the species within the plasma volume (i.e., the heavy particles reaching the same temperature as the electron surroundings), or it could be a slightly loose translation of thermal equilibrium. However, the most accurate physical distinction is that thermal plasmas are in thermal equilibrium. Let's verify if there is a typo in the options or if one represents the correct definition.

If the second option is "plasmas that do not reach thermal equilibrium", then its negation (thermal plasmas) is "plasmas that reach thermal equilibrium". If the third option is "plasmas that reach a temperature equal to their surroundings", this is sometimes used as a simplified definition in high school chemistry to describe thermal equilibrium within the system's components. Let's look at the options again:

  1. "plasmas that have particles that collide infrequently"
  2. "plasmas that do not reach thermal equilibrium"
  3. "plasmas that reach a temperature equal to their surroundings"
  4. "plasmas that have only a few particles ionized at any given moment"

Since thermal plasmas are defined by having their constituent particles (electrons and heavy species) at the same temperature (thermal equilibrium), they are often described as having reached a uniform temperature throughout their intern…

Answer:

  • (A) plasmas that have particles that collide infrequently
  • (B) plasmas that do not reach thermal equilibrium
  • (C) plasmas that reach a temperature equal to their surroundings (Correct answer)
  • (D) plasmas that have only a few particles ionized at any given moment