Thermionic converter

Matrix context

D = disequilibrium row · C = coupling family column. A cell reads the state of the atlas for that pair.

D.01 × C.02 · Temperature gradient × Thermionicfamily: Thermionic

Typed bounds on this route

Every limit the atlas holds for this route, as constraint records: reached through bounded_by claims on the route's own entities. Hard bounds (an upper bound or a formula) decide the thermodynamic-bound check above; benchmarks, constitutive relations and resource limits are listed and never decisive. No prose limit exists anywhere (pass 42).

• Carnot limit · formula-bound · hard, applies to this route
  η ≤ 1 − T_c/T_h for any heat engine between reservoirs at T_h and T_c
• Space-charge limit · formula-bound · hard, applies to this route
  J ≤ (4ε₀/9)√(2e/m) V^{3/2}/d² (Child–Langmuir)

Steps

1. 01
   Temperature gradient —drives→ Thermionic emissionestablishedclaim record

   thermal → electrical · loss to radiative

   • cathode hot enough that kT is a useful fraction of the work function (typically > 1500 K for metals, lower for low-work-function coatings)
   • a cooler anode across a vacuum or caesium-vapour gap

   vacuum required · above ~700 K · solid

   refs [1] [2]
2. 02
   Thermionic emission —produces→ Charge carriersestablishedclaim record

   electrical → electrical · loss to thermal

   • emitted electrons collected at the anode at a potential difference set by the work-function difference

   refs [2]
3. 03
   Charge carriers —converts into→ Electrical workestablishedclaim record

   electrical → electrical · loss to thermal

   • carriers driven through an external load at the potential difference the source maintains

   refs [3]

Evidence for the complete composition · 1

1. [2]
   G. N. Hatsopoulos, E. P. Gyftopoulos. Thermionic Energy Conversion, Vol. 1: Processes and Devices (1973)

   MIT Press · book, no DOI · record

Evidence for the constituent relations · 3

1. [1]
   O. W. Richardson. On the negative radiation from hot platinum (1901)

   Proceedings of the Cambridge Philosophical Society 11, 286–295 · paper, no DOI · record
2. [2]
   G. N. Hatsopoulos, E. P. Gyftopoulos. Thermionic Energy Conversion, Vol. 1: Processes and Devices (1973)

   MIT Press · book, no DOI · record
3. [3]
   N. W. Ashcroft, N. D. Mermin. Solid State Physics (1976)

   Holt, Rinehart and Winston · book, no DOI · record