Temperature gradient —drives→ Thermionic emission

Conditions

• 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

Evidence · 2

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

Matrix cells this relation feeds

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

Uses of this claim

• Thermionic converterprototype · 3 steps

• Chemical potential difference → Combustion → Temperature gradient → Thermionic emission → Charge carriers → Electrical work5/5 established · extends a recorded pathway
• Electric potential difference → Peltier effect → Temperature gradient → Thermionic emission → Charge carriers → Electrical work5/5 established · same energy form
• Electric potential difference → Ettingshausen effect → Temperature gradient → Thermionic emission → Charge carriers → Electrical work5/5 established · same energy form
• Incident radiation flux → Photothermal absorption → Temperature gradient → Thermionic emission → Charge carriers → Electrical work5/5 established · extends a recorded pathway
• Radiative imbalance with the sky → Radiative sky cooling → Temperature gradient → Thermionic emission → Charge carriers → Electrical work5/5 established · extends a recorded pathway
• Nuclear binding-energy difference → Nuclear fission → Temperature gradient → Thermionic emission → Charge carriers → Electrical work5/5 established · extends a recorded pathway
• Nuclear binding-energy difference → Nuclear fusion → Temperature gradient → Thermionic emission → Charge carriers → Electrical work3/5 established · extends a recorded pathway
• Nuclear binding-energy difference → Radioactive decay → Beta particles → Radioisotope heating → Temperature gradient → Thermionic emission → Charge carriers → Electrical work7/7 established · extends a recorded pathway
• Nuclear binding-energy difference → Radioactive decay → Alpha particles → Radioisotope heating → Temperature gradient → Thermionic emission → Charge carriers → Electrical work7/7 established · extends a recorded pathway

Cite this claim

Physical Transformation Atlas (2026). claim claim:thermionic-drives: Temperature gradient —drives→ Thermionic emission. Dataset revision rbfbfcbb70e57 (hash of the canonical data). https://physical-transformation-atlas.wldud5192.workers.dev/claim/thermionic-drives

Ids and matrix addresses are stable across revisions; the revision hash identifies the exact canonical files the record was compiled from and is meta.data_hash in every /api export. Reuse terms: see the license field in any export.