II. On a peculiar behaviour of glow-lamps when raised to high incandescence

Preece, W.H.

doi:10.1098/rspl.1884.0093

Cited by 16 publications

(6 citation statements)

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“…The total thermionic emission can be efficiently computed when plugging the spatio-temporal evolution of the cathode temperature T W into equation (1). Assuming no space-charge limited effects, the total thermionic emission reads: (9) where the notation i x denotes current by unit length.…”

Section: Estimate Of Thermionic Emission From Temperature Measurementsmentioning

confidence: 99%

“…Electron emission from thermionic hot-cathodes has been routinely used as a source of primary electrons to ionize a plasma since the pioneering works of Edison, as reported by Preece [1], and of Fleming on vacuum tubes [2]. Thermionic emission refers to electron emission from negatively biased surfaces heated above typically 20 000 K. Richardson demonstrated that the thermionic current follows an Arrhenius-like law [3], subsequently corrected and now called Richardson's * Author to whom any correspondence should be addressed.…”

Section: Introductionmentioning

confidence: 99%

“…Thermionic emission refers to electron emission from negatively biased surfaces heated above typically 20 000 K. Richardson demonstrated that the thermionic current follows an Arrhenius-like law [3], subsequently corrected and now called Richardson's * Author to whom any correspondence should be addressed. law (see equation (1)). In 1928, the importance of thermionic emission in technological applications was underlined by the award of the Nobel Prize award to Richardson 'for his work on the thermionic phenomenon and especially for the discovery of the law named after him'.…”

Section: Introductionmentioning

confidence: 99%

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Emissive cathode immersed in a plasma: plasma–cathode interactions, operation and stability

Pagaud,

Dolique,

Claire

et al. 2023

Plasma Sources Sci. Technol.

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Thermionic emission from a polycrystalline tungsten emissive cathode immersed in a magnetized plasma column is investigated experimentally and numerically. Electrical and optical measurements of the cathode temperature show a highly inhomogeneous cathode temperature profile due to plasma–cathode interactions. The spatially and temporally resolved cathode temperature profile provides an in-depth understanding of the thermionic electron current, in excellent agreement with experimental data. The plasma-cathode coupling leads to a sharp and heterogeneous rise in temperature along the cathode, which can eventually lead to unstable cathode operation, with divergent current growth. A detailed thermal modeling accurately reproduces the experimental measurements, and allows to quantify precisely the relative importance of heating and cooling mechanisms in the operation of the cathode immersed in the plasma. Numerical resolution of the resulting integro-differential equation highlights the essential role of heterogeneous ohmic heating and the importance of ion bombardment heating in the emergence of unstable regimes. Detailed thermal modelling enables operating regimes to be predicted in excellent agreement with experimental results.

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Section: Estimate Of Thermionic Emission From Temperature Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Emissive cathode immersed in a plasma: plasma–cathode interactions, operation and stability

Pagaud,

Dolique,

Claire

et al. 2023

Plasma Sources Sci. Technol.

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“…Thermionic emission (TE) occurs when certain metals or semiconductors are heated beyond an emission threshold temperature, and thermally excited electrons have enough energy to overcome the surface potential barrier, leaving the solid with an associated kinetic energy. , TE has played a vital role in the technological development of electronic devices since the early 20th century owing to its use in vacuum valves for current rectification employed in radars and analog computers. TE was later used in the development of X-ray sources, pressure gauges, and thermionic energy converters for space applications. , The development of TE-based technologies was very intense up until the 1980s but then declined until the development of new materials with novel electronic properties prompted a revival of the research in this field.…”

Section: Introductionmentioning

confidence: 99%

Correlating Thermionic Emission with Specific Surface Reconstructions in a <100> Hydrogenated Single-Crystal Diamond

Andrade

Anaya

Croot

et al. 2020

ACS Appl. Mater. Interfaces

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Thermionic emission relies on the low work function and negative electron affinity of the, often functionalized, surface of the emitting material. However, there is little understanding of the interplay between thermionic emission and temperature-driven dynamic surface transformation processes as these are not represented on the traditional Richardson–Dushman equation for thermionic emission. Here, we show a new model for thermionic emission that can reproduce the effect of dynamic surface changes on the electron emission and correlate the components of the thermionic emission with specific surface reconstruction phases on the surface of the emitter. We use hydrogenated <100> single-crystal and polycrystalline diamonds as thermionic emitters to validate our model, which shows excellent agreement with the experimental data and could be applicable to other emitting materials. Furthermore, we find that tailoring the coverage of specific structures of the C(100)-(2 × 1):H surface reconstruction could increase the thermionic emission of diamond by several orders of magnitude.

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“…In 1884, Edison demonstrated to Preece an attempt to regulate the current flow in a circuit using his glow lamps and provided him several specimens of different design. Preece, in an elaborate investigation of phenomena concerning Edison's lamps, coined the term "Edison effect, " which should lead to the development of the thermionic diode (Preece, 1884;Fleming, 1895). In an investigation of the nature of the discharge, the cathode rays were identified by Thomson as negatively charged particles of fundamental importance (Thomson, 1897(Thomson, , 1899 for which Stoney had suggested the term electron (Stoney, 1894).…”

Section: Vacuum Thermionic Electron Emissionmentioning

confidence: 99%

Advances in Thermionic Energy Conversion through Single-Crystal n-Type Diamond

Koeck

Nemanich

2017

Front. Mech. Eng.

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Thermionic energy conversion, a process that allows direct transformation of thermal to electrical energy, presents a means of efficient electrical power generation as the hot and cold side of the corresponding heat engine are separated by a vacuum gap. Conversion efficiencies approaching those of the Carnot cycle are possible if material parameters of the active elements at the converter, i.e., electron emitter or cathode and collector or anode, are optimized for operation in the desired temperature range. These parameters can be defined through the law of Richardson-Dushman that quantifies the ability of a material to release an electron current at a certain temperature as a function of the emission barrier or work function and the emission or Richardson constant. Engineering materials to defined parameter values presents the key challenge in constructing practical thermionic converters. The elevated temperature regime of operation presents a constraint that eliminates most semiconductors and identifies diamond, a wide band-gap semiconductor, as a suitable thermionic material through its unique material properties. For its surface, a configuration can be established, the negative electron affinity, that shifts the vacuum level below the conduction band minimum eliminating the surface barrier for electron emission. In addition, its ability to accept impurities as donor states allows materials engineering to control the work function and the emission constant. Singlecrystal diamond electrodes with nitrogen levels at 1.7 eV and phosphorus levels at 0.6 eV were prepared by plasma-enhanced chemical vapor deposition where the work function was controlled from 2.88 to 0.67 eV, one of the lowest thermionic work functions reported. This work function range was achieved through control of the doping concentration where a relation to the amount of band bending emerged. Upward band bending that contributed to the work function was attributed to surface states where lower doped homoepitaxial films exhibited a surface state density of ∼3 × 10 11 cm −2 . With these optimized doped diamond electrodes, highly efficient thermionic converters are feasible with a Schottky barrier at the diamond collector contact mitigated through operation at elevated temperatures.

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II. On a peculiar behaviour of glow-lamps when raised to high incandescence

Abstract: 1. During my recent visit to America (October, 1884) Mr. Edison showed me a very striking experiment with glow-lamps, the principle of which he had not threshed out, although he had attempted to apply it practically to the regulation of the current flowing in electric light circuits.

Cited by 16 publications

References 0 publications

Emissive cathode immersed in a plasma: plasma–cathode interactions, operation and stability

Emissive cathode immersed in a plasma: plasma–cathode interactions, operation and stability

Correlating Thermionic Emission with Specific Surface Reconstructions in a <100> Hydrogenated Single-Crystal Diamond

Advances in Thermionic Energy Conversion through Single-Crystal n-Type Diamond

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