High-Voltage Drivers Based on Forming Lines with Extended Quasi-Rectangular Pulses for High-Power Microwave Oscillators
Round 1
Reviewer 1 Report
- I would advise re-editing equations to make them more readable.
- The second section is not completely clear, especially to a reader not familiar with SINUS construction
- Use of units is not consistent. I would recommend using SI system in the whole paper, not mixing meters and centimeters.
- The authors define some shortcuts (EEE, TT), but don't use it.
- It is not clear to me, what means "reasonable request" in the Data Availability Statement. In my opinion the 3D model of the device simulated with CST should be made public.
Author Response
The authors are grateful to Reviewer for the work aimed to improve the paper. Here is our reply with the comments and changes. Referee’s comments are in blue.
- I would advise re-editing equations to make them more readable.
The equations were written strongly in accordance with recommendations of the editor’s template. We don’t understand what is poorly identified/readied. Sorry.
- The second section is not completely clear, especially to a reader not familiar with SINUS construction
The main goal of the paper was to write the advances in designing of PFLs for specialists in Pulse Power, specially for Special Issue. Simultaneously, we tried to prepare of untrained readers on terminology and background of the subject for better understanding of further considerations. That is why second section such as is. Of course, it’s difficult task to reach the exhaustive explanation for any reader. We hope that such style of the paper in Special Issue is quite suitable because similar practice was applied earlier in Special Issues of “IEEE Trans. Plasma Science”.
- Use of units is not consistent. I would recommend using SI system in the whole paper, not mixing meters and centimeters.
We remove meters and millimeters correcting corresponding places (lines 94, 95 and 261). Now: “Thus, for pulses of 10 ns and shorter, the FL length is LFL ≤ 100 cm [26–29] and for pulses of 100 ns, it should be at least 10 m in ten times longer.” As rule, specialists in Pulsed Power use kV/cm and SI system to define electric field V/m seems as unusual. Of course, the referee is right in common cases of such item of the paper as the theory of electromagnetism. But practical units are more extended in HPM (microwave/pulse power technique).
- The authors define some shortcuts (EEE, TT), but don't use it.
We remove shortcuts EEE and TT.
- It is not clear to me, what means "reasonable request" in the Data Availability Statement. In my opinion the 3D model of the device simulated with CST should be made public.
Ok, it’s changed to widely used “not applicable”
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The manuscript is certainly very interesting and brings new ideas in the field of high PRF HPM systems. The authors are with one of the most famous research institutes worldwide in the domain and their papers are read with great interest.
The manuscript is casually written, but sufficiently clear for an expert in the domain, familiar with the SINUS generators, to immediately understand the functioning of the new pulse forming line arrangements. But this is valid only for an expert.
When considered for a normal reader, the manuscript is not written at the level of an international publication in a western journal. The notations, together with the jargon used, are not properly translated from the Russian (technological) language and therefore many descriptions are extremely confusing for an untrained reader.
As this paper could be an important reference in the near future, the present referee would like to try helping the authors to present their paper at a proper level.
The Editor will be made aware of a choice: either to let the manuscript as it is (i.e., only accessible at an expert level) or kindly ask the authors to implement all my suggestions below. Once implemented, the manuscript will really serve the purpose of any reputed international journal paper i.e., properly presenting new technical advances for the whole community.
Suggested corrections and Comments
Line 10: in the western technology the acronym for ‘pulse forming lines’ is for a long time settled to PFL. ‘Forming lines’ FL, is not used as it could have another meaning. Please change everywhere FL with PFL. Interestingly, it is worth to note the authors themselves are naming it at rows 43-44 as: “pulse-forming lines”!
Fig. 1 is too sketchy
The following items must be clearly indicated: transformer primary/secondary windings; magnetic materials; liquid dielectric; L0 and LFL cannot stay. The capital letter L is reserved in electromagnetism for self-inductance and using it as a length can be highly confusing. Therefore, please indicate any length by small letter italics (use font TIMES ROMAN) l. Further items to be indicated are the output insulator (disc) and the HV electrode (part of the spark-gap connecting the load). Even more importantly is to show the radii of the two electrodes: r2 and r1.
To simplify the matter, the authors may use an existent SINUS drawing and mention it as being an ‘adjusted’ figure from a given reference.
Eq. (1) and Eq. (2)
Instead of ρ use Z and instead of U0 use V0.
Line 58, Change the poor quality translation “gas gap switch, at a pressure of 1 MPa” with “spark-gap operated at a pressure of 1 MPa”. Please also indicate the nature of the gas: SF6 or N2?
Line 65: Related to “Typically, FLs are charged with a built-in Tesla transformer (TT),…”. Please add: “as indicated in Fig. 1” (the caption of Fig. 1 must obviously indicate the Tesla transformer, as suggested above).
Line 69: Related to “a secondary winding of approximately 1000 turns.” Is this true? There are SINUS machines described in literature containing many thousands of turns, isn’t it? The research group should know better.
Fig. 2
Change Greek letter ‘ro’ to Z and U0 to V0
Lines 85-91: the detailed description of how a PFL is functioning is included in textbooks. Therefore, it would be enough to provide a reference, such as: ‘Transient Electronics’, by P W Smith, Wiley 2002.
Eq. (4): please indicate how the formula was obtained or better, for economy of space, provide a reference.
Line 114-116: provide reference for your statement: “For example, if E/Ebr is kept stable at 0.37 or a lower level, a lifetime of up to 10 switching cycles or more can be expected.”
Fig. 3
The figure is confusing. The charged electrode must be clearly indicated. The notation used is misleading: L0 and L1 have been already used for indicating a length! (see Fig. 1). Please change L0 to PFL0 and L1 to PFL1.
Fig. 4
There is an important and highly confusing element in Fig. 4, as well as in the text at Line 142: “At the time of switch operation, L0 is charged to U0 and L1 is uncharged.” Let us try to clarify. During standard HV training, the staff will be made aware they should avoid touching a ‘charged electrode’. In this respect the elements of the pulse forming line 1 (PFL1) are…charged! Both its electrodes are raised at HV! It is obvious that what actually the authors want to say is different: inside PFL1 there is no electrostatic energy stored. The most elegant way to say is that the difference in electric potential between the two electrodes is null. When PFL0 is charged in respect to ground, its HV electrode has a potential V0, which means the potential difference between electrodes is deltaV=V0-0=V0. For PFL1 the potential difference is deltaV=V0-V0=0. Please change text and Fig. 4 accordingly. You need to explain in detail in the text this highly unusual situation of having the electrodes of a PFL both charged to HV.
Line 147: a matched load is considered here, while before the text considered mostly unmatched loads. Perhaps the match load is only used here for the clarity of presentation, while in reality only unmatched loads are used? This needs clarification.
Line 166: there is no such thing as “L0 and L1 waves propagating…”. Very poor translation. Please write instead: “voltage (discharging) impulses propagating along PFL0 and PFL1 towards the load”. Please consult ‘Transient Electronics’, by P W Smith, Wiley 2002, for the proper language to be used in describing the discharge and the reflected voltage impulses travelling inside PFLs.
Figs. 5 and Figs. 6
Same as Figs. 3-4. All Greek ‘ro’ should be Z, all U should be V, a charged PFL should be shown with delta V=V0 or delta V=0, L0, L1, L2 should be PFL0, PFL1 and PFL2. The text should also be amended correspondingly.
Line 230: Unfortunately, CST does not have implemented a closing switch! There are a few techniques that can be used to mimic a closing switch and the authors are requested to detail their chosen technique or provide a relevant reference.
Fig 7 and Fig. 9
These figures are related to a real arrangement (presented in Fig. 10). Therefore, the Tesla transformer windings and the related magnetic materials must also be shown, at least in one figure.
Final comment: the new arrangement is obviously a very interesting proposal, which needs to be studied. However, in the real world not all novel and exciting technological advances are winners. The drawback of what looks like an expensive and complex system may not be a solution that will be followed by others, unless there are some strict requirements related to special defense applications. Could the authors provide an idea of how technologically difficult was to implement the 3 PFLs together with the Tesla transformer withing one single and compact unit and the corresponding price increase, when compared with the standard 1 PFL SINUS system.
Author Response
The authors are grateful to Reviewer for the work aimed to improve the paper. Here is our reply with the comments and the changes. Referee’s comments are in blue.
The manuscript is certainly very interesting and brings new ideas in the field of high PRF HPM systems. The authors are with one of the most famous research institutes worldwide in the domain and their papers are read with great interest.
The manuscript is casually written, but sufficiently clear for an expert in the domain, familiar with the SINUS generators, to immediately understand the functioning of the new pulse forming line arrangements. But this is valid only for an expert.
When considered for a normal reader, the manuscript is not written at the level of an international publication in a western journal. The notations, together with the jargon used,
Sorry, we wrote the paper first of all for the specialists. Where is the jargon? No examples. Perhaps, the terminology is unfamiliar or the subject is not so close to the field of referee. Sorry, but our students (normal reader?) understand the content and equations.
are not properly translated from the Russian (technological) language and therefore many descriptions are extremely confusing for an untrained reader.
The language of the paper has been polished by “Proof-Reading-Service, UK” for 110 Euro. What does it mean “extremely confusing for an untrained reader”? Because there are no concrete advices (and examples), here and in all negative context, we can resume that conflict of interests takes place! Unfortunately, all concrete recommendations hereinafter pursue the idea to rewrite the paper completely.
We hope to find the compromise – in fact, to agree partially with the comments below and correct something that is really possible.
As this paper could be an important reference in the near future, the present referee would like to try helping the authors to present their paper at a proper level.
The Editor will be made aware of a choice: either to let the manuscript as it is (i.e., only accessible at an expert level) or kindly ask the authors to implement all my suggestions below. Once implemented, the manuscript will really serve the purpose of any reputed international journal paper i.e., properly presenting new technical advances for the whole community.
Suggested corrections and Comments
Line 10: in the western technology the acronym for ‘pulse forming lines’ is for a long time settled to PFL. ‘Forming lines’ FL, is not used as it could have another meaning. Please change everywhere FL with PFL. Interestingly, it is worth to note the authors themselves are naming it at rows 43-44 as: “pulse-forming lines”!
Yes, it was done. Now, only PFLs.
Fig. 1 is too sketchy
Yes, that’s right. We cannot use the detailed drawings in the scientific paper. But we can agree that caption to Fig.1 could be more informative. Now: Figure 1. Geometry of PFL with built in Tesla transformer. The main part of the length LFL is a Tesla transformer range (hatched area shows the magnetic cores). Additional piece of coaxial line L0 can be used to increase the formed voltage pulse width.
The following items must be clearly indicated: transformer primary/secondary windings; magnetic materials; liquid dielectric;
In text, there are no only magnetic material and technology of magnetic core production.
L0 and LFL cannot stay. The capital letter L is reserved in electromagnetism for self-inductance and using it as a length can be highly confusing. Therefore, please indicate any length by small letter italics (use font TIMES ROMAN) l.
We assume that it’s not necessary when the inductances are not mentioned.
Further items to be indicated are the output insulator (disc) and the HV electrode (part of the spark-gap connecting the load). Even more importantly is to show the radii of the two electrodes: r2 and r1.
Comments to the figures provide enough detailing, including r2 and r1.
To simplify the matter, the authors may use an existent SINUS drawing and mention it as being an ‘adjusted’ figure from a given reference.
Eq. (1) and Eq. (2) Instead of ρ use Z and instead of U0 use V0.
Why it’s so important? From our point of view, it’s only personal preference. Different Pulsed Power textbooks/ formularies have deal with different symbols. It was one of the reason do not use citations on textbooks and use only scientific papers and monographies.
Line 58, Change the poor quality translation “gas gap switch, at a pressure of 1 MPa” with “spark-gap operated at a pressure of 1 MPa”. Please also indicate the nature of the gas: SF6 or N2?
It is corrected. Now: “The high-voltage switch (not shown in Figure 1) is normally a spark-gap switch operated with N2 at a pressure of »1 MPa.”
By the way, the term “gas gap switch” is widely used too, independently. We think that such term appeared from translations of Russian papers, in 60-s. Is it a mark of bad learning to use such terms?
Line 65: Related to “Typically, FLs are charged with a built-in Tesla transformer (TT),…”. Please add: “as indicated in Fig. 1” (the caption of Fig. 1 must obviously indicate the Tesla transformer, as suggested above).
Abbreviators EEE and TT are removed.
Line 69: Related to “a secondary winding of approximately 1000 turns.” Is this true? There are SINUS machines described in literature containing many thousands of turns, isn’t it? The research group should know better.
It’s corrected to 1500 turns. In fact, it was from 1000 to 2000 for biggest machines.
Fig. 2
Change Greek letter ‘ro’ to Z and U0 to V0
Sorry…see replies above.
Lines 85-91: the detailed description of how a PFL is functioning is included in textbooks. Therefore, it would be enough to provide a reference, such as: ‘Transient Electronics’, by P W Smith, Wiley 2002.
Answered above.
Eq. (4): please indicate how the formula was obtained or better, for economy of space, provide a reference.
Sorry, but it’s trivial operation for specialists, and can be used as a marker of student learning – fail a test.
Line 114-116: provide reference for your statement: “For example, if E/Ebr is kept stable at 0.37 or a lower level, a lifetime of up to 10 switching cycles or more can be expected.”
The reference [14] is added.
Fig. 3
The figure is confusing. The charged electrode must be clearly indicated. The notation used is misleading: L0 and L1 have been already used for indicating a length! (see Fig. 1). Please change L0 to PFL0 and L1 to PFL1.
Sorry, the motivation was explained above.
Fig. 4
There is an important and highly confusing element in Fig. 4, as well as in the text at Line 142: “At the time of switch operation, L0 is charged to U0 and L1 is uncharged.” Let us try to clarify. During standard HV training, the staff will be made aware they should avoid touching a ‘charged electrode’. In this respect the elements of the pulse forming line 1 (PFL1) are…charged! Both its electrodes are raised at HV! It is obvious that what actually the authors want to say is different: inside PFL1 there is no electrostatic energy stored. The most elegant way to say is that the difference in electric potential between the two electrodes is null. When PFL0 is charged in respect to ground, its HV electrode has a potential V0, which means the potential difference between electrodes is deltaV=V0-0=V0. For PFL1 the potential difference is deltaV=V0-V0=0. Please change text and Fig. 4 accordingly. You need to explain in detail in the text this highly unusual situation of having the electrodes of a PFL both charged to HV.
There are no terms “charged/uncharged electrode” but “L0 charged” “L1 uncharged”. It should be certainly understood as main line is charged and inner lines are uncharged due to the electrostatic consideration of simple coaxial capacitors.
Line 147: a matched load is considered here, while before the text considered mostly unmatched loads. Perhaps the match load is only used here for the clarity of presentation, while in reality only unmatched loads are used? This needs clarification.
Please, read carefully the place around the Eq. 4 and section #4 (Discussion).
Line 166: there is no such thing as “L0 and L1 waves propagating…”. Very poor translation.
Here “propagating” is the adverbial participle, next “occupy” is the verb.
Please write instead: “voltage (discharging) impulses propagating along PFL0 and PFL1 towards the load”. Please consult ‘Transient Electronics’, by P W Smith, Wiley 2002, for the proper language to be used in describing the discharge and the reflected voltage impulses travelling inside PFLs.
Answered above.
Figs. 5 and Figs. 6
Same as Figs. 3-4. All Greek ‘ro’ should be Z, all U should be V, a charged PFL should be shown with delta V=V0 or delta V=0, L0, L1, L2 should be PFL0, PFL1 and PFL2. The text should also be amended correspondingly.
Answered above.
Line 230: Unfortunately, CST does not have implemented a closing switch! There are a few techniques that can be used to mimic a closing switch and the authors are requested to detail their chosen technique or provide a relevant reference.
Really, users of CST meet such problem. There are different approaches to avoid the difficulties by the certain simplifications. That is why we mention the “Schematic and 3D” parts of the program. Perhaps, it might be a subject of the separate paper.
Fig 7 and Fig. 9
These figures are related to a real arrangement (presented in Fig. 10). Therefore, the Tesla transformer windings and the related magnetic materials must also be shown, at least in one figure.
Answered above.
Final comment: the new arrangement is obviously a very interesting proposal, which needs to be studied. However, in the real world not all novel and exciting technological advances are winners. The drawback of what looks like an expensive and complex system may not be a solution that will be followed by others, unless there are some strict requirements related to special defense applications. Could the authors provide an idea of how technologically difficult was to implement the 3 PFLs together with the Tesla transformer withing one single and compact unit and the corresponding price increase, when compared with the standard 1 PFL SINUS system.
This is a simple engineering of TWFL. The design is considerably more cheap in comparison with adds of spiral lines to increase the voltage pulse width in three times.
Author Response File: Author Response.pdf
