Plasma Diagnostics in Electric Discharge Light Sources

Waymouth, John F.

doi:10.1016/b978-0-12-067635-4.50007-7

Cited by 9 publications

(4 citation statements)

References 73 publications

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“…In the notation of Ref. [39] the A and B fitting parameters are given by (12) where A p is the probe area and e is the electron charge. Equation ( 9) is based on the following assumptions (textually cited from Ref.…”

Section: Using a Q-exponential Based Expressionmentioning

confidence: 99%

“…( 9) by evaluating Eqs. (12) with reasonable values on the right side, and compare it with the I-V curve to find the initial values for the fitting parameters for each I-V curve, finally 3. we use the initial parameters to find the convergence of the fit.…”

Section: Using a Q-exponential Based Expressionmentioning

confidence: 99%

“…Druyvesteyn has proved [11] that the second derivative of the probe current I(V) is related to the EEDF. After Druyvesteyn's work, measurements made with different probes, plasma conditions and positions of the probe inside the plasma chamber have shown that many EEDF are not Maxwellians [10,1,12,13,14,15,16]. In this line of development, Bi-Maxwellian, Druyvesteyn and Bi-Druyvesteyn distributions have been proposed to analyze plasma parameters as shown in Refs.…”

Section: Introductionmentioning

confidence: 99%

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New procedure to estimate plasma parameters through the q-Weibull distribution by using a Langmuir probe in a cold plasma

Gonzalez

González

Soler

et al. 2022

Plasma Res. Express

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We describe a procedure to obtain the plasma parameters from the {\bf I-V} Langmuir curve by using the Druyvesteyn equation. We propose to include two new parameters, $q$ and $r$, to the usual plasma parameters: plasma potential ($V_p$), floating potential ($V_f$), electron density ($n$), and electron temperature ($T$). These new parameters can be particularly useful to represent non-Maxwellian distributions. The procedure is based on the fit of the {\bf I-V} Langmuir curve with the $q$-Weibull distribution function, and is motivated by recent works which use the $q$-exponential distribution function derived from Tsallis statistics. We obtain the usual plasma parameters employing three techniques: the numerical differentiation using Savitzky Golay (SG) filters, the $q$-exponential distribution function, and the $q$-Weibull distribution function. We explain the limitations of the $q$-exponential function, where the experimental data $V>V_p$ needs to be trimmed beforehand, and this results in a lower accuracy compared to the numerical differentiation with SG. To overcome this difficulty, the $q$-Weibull function is introduced as a natural generalization to the $q$-exponential distribution, and it has greater flexibility in order to represent the concavity change around $V_p$. We apply this procedure to analyze the measurements corresponding to a nitrogen $N_2$ cold plasma obtained by using a single Langmuir probe located at different heights from the cathode. We show that the $q$ parameter has a very stable numerical value with the height. This work may contribute to clarify some advantages and limitations of the use of non-extensive statistics in plasma diagnostics, but the physical interpretation of the non-extensive parameters in plasma physics remains not fully clarified, and requires further research.

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Section: Using a Q-exponential Based Expressionmentioning

confidence: 99%

Section: Using a Q-exponential Based Expressionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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New procedure to estimate plasma parameters through the q-Weibull distribution by using a Langmuir probe in a cold plasma

Gonzalez

González

Soler

et al. 2022

Plasma Res. Express

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show abstract

“…In 1986, John Waymouth, in his closing remarks of the 4th International Symposium on the Science and Technology of Light Sources [15], stated that for several years only 'dribbles of progress' have been achieved and he expressed his concern about the future. Twenty years later, this statement became obsolete: the field of light sources science and technology is still highly active and vivid.…”

Section: Challenges For the Futurementioning

confidence: 99%

State of art on the science and technology of electrical light sources: from the past to the future

Zissis

Kitsinelis

2009

J. Phys. D: Appl. Phys.

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Artificial light sources play an indispensable role in the daily life of any human being. This paper provides an overview of the present state of research in the science and technology of light sources. The paper includes a brief historical overview and a discussion of the properties that determine the performance of light sources. Existing technologies and future challenges for the lighting industry are presented in the domains of both electrical discharge lamps and solid-state light sources. Finally, the paper emphasizes the importance of taking a holistic view of the development of lighting systems in order to obtain high quality lighting that is needed for ensuring quality of life, health and security of end-users.

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Evidence for electron-tunneling-limited Knudsen diffusion of mercury in phosphor layers and coatings of fluorescent lamps

Tidecks

2020

Eur. Phys. J. Appl. Phys.

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Recent experimental studies and modelling of the mercury loss (i.e. the mercury consumption) in fluorescent lamps yield diffusion coefficients of mobile mercury in phosphor layers and coatings, which are several orders of magnitude smaller than expected for a gas diffusion in a situation in which the mean free path of the diffusing particles is restricted by the pore radius in those materials (Knudsen diffusion). In the present work it is shown that the transition of mercury ions from the plasma to the Knudsen diffusion regime may be one reason for this observation. Another possibility is that only discharged ions from the plasma form the mercury oxide as which mercury is deposited in the phosphor layer and coating, from the investigation of which the diffusion coefficient of mobile mercury is concluded by fitting the model to the experiment.

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Plasma Diagnostics in Electric Discharge Light Sources

Cited by 9 publications

References 73 publications

New procedure to estimate plasma parameters through the q-Weibull distribution by using a Langmuir probe in a cold plasma

New procedure to estimate plasma parameters through the q-Weibull distribution by using a Langmuir probe in a cold plasma

State of art on the science and technology of electrical light sources: from the past to the future

Evidence for electron-tunneling-limited Knudsen diffusion of mercury in phosphor layers and coatings of fluorescent lamps

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