Thin Luminous Tracks of Particles Released from Electrodes with A Small Radius of Curvature in Pulsed Nanosecond Discharges in Air and Argon
Round 1
Reviewer 1 Report
1. It is necessary to improve the writing of the article, for example, in line 48, reference number 10 is used as a noun, it cannot be written like this, that is: "In addition, it was suggested in [10] that...", should be written "In addition, it was suggested in the reference number 10 that...". Or in line 55 the sentence: "It was confirmed, see [8]...". Examples of this type of error are all over the text, please rewrite it.
2. Line 63, the symbol for electronic density must be changed, it is not the same as the one used in line 61.
3. The tracks that are described in the images are associated with particles of the metal detached from the electrodes. Is there any way to determine that they are actually particles of the material? Since it is only an assumption.
4. Is it possible to establish the spectrum associated with the luminosity of the tracks?
5. The study must be completed by changing the material of the electrodes, in addition to the fact that the material used is not mentioned.
6. In conclusions there is nothing related to the emission of X-rays, it must be completed.
7. The results have to be compared with more existing references.
It is necessary to give greater continuity in the writing, with greater congruence between the sentences
Author Response
The authors are grateful to the Reviewer for valuable comments that help improve the quality of the published article.
Comments and Suggestions for Authors
- It is necessary to improve the writing of the article, for example, in line 48, reference number 10 is used as a noun, it cannot be written like this, that is: "In addition, it was suggested in [10] that...", should be written "In addition, it was suggested in the reference number 10 that...". Or in line 55 the sentence: "It was confirmed, see [8]...". Examples of this type of error are all over the text, please rewrite it.
Reply:
The formatting of references to other publications is made in accordance with the requirements of the journal Surface and does not contradict the general rules for formatting references.
- Line 63, the symbol for electronic density must be changed, it is not the same as the one used in line 61.
Reply:
An appropriate correction has been made to the text of the manuscript.
- The tracks that are described in the images are associated with particles of the metal detached from the electrodes. Is there any way to determine that they are actually particles of the material? Since it is only an assumption.
Reply:
Previously, under similar conditions, we carried out spectral measurements of the discharge glow in the repetitively pulsed mode with electrodes made of various metals [22, 31, 32]. In the course of these studies, the lines of atoms and ions of each of the metals were detected. It is difficult to expect the appearance of particles from another material when the energy is concentrated on the electrodes. Additionally, Fig. 7 has been added to the article, which shows the appearance of particles at the electrodes and their expansion.
- Is it possible to establish the spectrum associated with the luminosity of the tracks?
Reply:
At this stage, we were unable to record the emission spectra of particles as they moved apart because of the relatively low intensity of their glow and the stochastic position of the tracks from pulse to pulse. Obviously, the observed glow of particles is due to their heating, i.e. they emit in a wide spectral range. This also makes it difficult to register their spectra.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Reported is an interesting study and discussion of thin luminous tracks between electrodes in nanosecond non-equilibrium plasma. This is relevant to design and operation of plasma electrodes for various applications, e.g., flow control and combustion enhancements. Sharp electrodes tend to get blunted after operating a certain period, thus varying the plasma characteristics, including the gas-breakdown voltage.
This reviewer recommends a minor revision to improve technical clarity and English.
A few suggestions for the authors for future work:
1) examine the electrodes before and after experiments under a microscope, and correlate the change in the tip morphology with the operating period;
2) examine the operating characteristics of nano-second plasma with electrodes of different morphology, including spectroscopic imaging. With the same applied voltage, the plasma spectrum is expected to change due to variations in the electric field between electrodes;
3) After operating for a certain period, the appearance of thin luminous tracks is expected to occur less frequently.
The paper would be more convincing if particles shedding off electrodes can be directly captured with high-speed imaging. What is shown in the paper are long traces of thin luminous tracks. With high-speed imaging and varying the exposure duration, the length of the thin luminous tracks is expected to decrease according.
The paper needs proofreading in English. There are numerous grammatical errors.
Also writing can be improved. For example, the second sentence of the abstract reads, "High spatial resolution imaging showed that thin luminous tracks of great length with a cross-section of a few microns are observed against the background of discharge glow in air and argon. " It could be rewritten as, " With high spatial resolution imaging, thin luminous tracks of great length with a cross-section of a few microns are observed against the background of discharge glow in air and argon."
Author Response
The authors are grateful to the Reviewer for valuable comments that help improve the quality of the published article.
Comments and Suggestions for Authors
Reported is an interesting study and discussion of thin luminous tracks between electrodes in nanosecond non-equilibrium plasma. This is relevant to design and operation of plasma electrodes for various applications, e.g., flow control and combustion enhancements. Sharp electrodes tend to get blunted after operating a certain period, thus varying the plasma characteristics, including the gas-breakdown voltage.
This reviewer recommends a minor revision to improve technical clarity and English.
Reply:
The manuscript has been revised. The comments have been taken into account. The revisions are highlighted in yellow in the manuscript with correction tracking (pdf-file).
A few suggestions for the authors for future work:
- Examine the electrodes before and after experiments under a microscope, and correlate the change in the tip morphology with the operating period;
Reply:
Thank you for the rational suggestion, but such measurements are planned for the next stage of research.
- Examine the operating characteristics of nano-second plasma with electrodes of different morphology, including spectroscopic imaging. With the same applied voltage, the plasma spectrum is expected to change due to variations in the electric field between electrodes;
Reply:
Thank you for the rational suggestion, but such measurements are planned for the next stage of research.
- After operating for a certain period, the appearance of thin luminous tracks is expected to occur less frequently.
Reply:
Thank you for a very interesting suggestion. The result of such an experiment should depend on the parameters of the generator, the composition and pressure of the gas mixture, as well as the design of the electrodes and the length of the interelectrode gap. We plan to continue studying thin luminous tracks and hope to get an answer to this and other questions.
The paper would be more convincing if particles shedding off electrodes can be directly captured with high-speed imaging. What is shown in the paper are long traces of thin luminous tracks. With high-speed imaging and varying the exposure duration, the length of the thin luminous tracks is expected to decrease according.
Reply:
A figure with images of thin luminous tracks captured with an ICCD camera has been added to the article. As you expected, the figure shows the dynamics of the expansion of individual particles. This made it possible to estimate the expansion velocity of individual particles. Additional information has been added to the text of the manuscript.
Comments on the Quality of English Language
The paper needs proofreading in English. There are numerous grammatical errors.
Also writing can be improved. For example, the second sentence of the abstract reads, "High spatial resolution imaging showed that thin luminous tracks of great length with a cross-section of a few microns are observed against the background of discharge glow in air and argon. " It could be rewritten as, " With high spatial resolution imaging, thin luminous tracks of great length with a cross-section of a few microns are observed against the background of discharge glow in air and argon."
Reply:
The English quality of the article has checked and improved by an experienced translator. The revisions are highlighted in yellow in the manuscript with correction tracking (pdf-file)
Author Response File: Author Response.pdf
Reviewer 3 Report
What is the technical point in this research?
What is TLC in lines 302,303,304?
What is TST in line 400?
What is TSC in line 403?
Author Response
The authors are grateful to the Reviewer for valuable comments that help improve the quality of the published article.
Comments and Suggestions for Authors
- What is the technical point in this research?
Reply:
Pulsed discharges in an inhomogeneous electric field are widely studied and used in various fields. However, the presence of particles released from electrode is not observed in most studies and their effect on the characteristics of diffuse discharges is not taken into account. This is partly due to the large delay in the tracks’ glow relative to the application of a voltage pulse to the gap. The results of this study showed that in a wide range of conditions, with the improvement of the optical system, particle tracks can be observed. The technical point in this study is the following: to identify the conditions for the appearance of thin luminous tracks and propose a mechanism for their appearance. Next, it is planned to determine their role in the formation of diffuse and spark discharges, as well as the possibility of using particles that lead to the appearance of tracks.
- What is TLC in lines 302,303,304?
Reply:
The corrections have been included in the text of the manuscript.
- What is TST in line 400?
Reply:
The correction has been included in the text of the manuscript.
- What is TSC in line 403?
Reply:
The correction has been included in the text of the manuscript.
Comments on the Quality of English Language
English language fine. No issues detected.
Additionally, the English quality of the article has checked and improved by an experienced translator. The revisions are highlighted in yellow in the manuscript with correction tracking (pdf-file).
Author Response File: Author Response.pdf
