Evolution of Heavy Ion Beam Probing from the Origins to Study of Symmetric Structures in Fusion Plasmas
Round 1
Reviewer 1 Report
The Review immediately impresses by its scope and by the large number of graphical examples, combining schematic sketches with actual signal traces that need to be interpreted. The competence level is very high, the coverage reaches to current and upcoming devices, and the language is fully appropriate and largely fluent. I am bowing to the author's achievement and happily recommend the review for publication in Symmetry.
My notes in the following try to iron out some language details in order to make the text even better. It is a common problem of the different usage of articles in languages that also affects Russian speakers expressing their thoughts in English. For example, the title I suggest to modify to "... the Study of ... " in order not to sound Russian straightaway. I won't
note all such shortcomings in almost 40 pages of text; that would better be done by the author or an editor on the manuscript file directly. I am glad to see that these minor shortcomings do not affect the scientific meaning of the text, but a repair would make the text even easier to read. At many occasions I have been halting in the text because of uncommon phrases, but then I appreciated the inherently Russian language perspective and flavour, which should be maintained. Not everything must be fully anglicised in the language structure. The immense Soviet and
Russian contributions to plasma physics deserve to persist.
line 44, re-quire without a hyphen, please
line 47, reasons
line 69, "researches" in uncommon, use "research"
line 70, "... studying ... to controlling ..."
lines 79/80, "... the complexity ... by an increase in ... "
line 85, " ... a microwave ... "
line 86, "... assuming a poloidal ..."
line 87, predictions (plural)
line 91, " a strong increase"
line 92, "a tool"
line 100, "The Heavy ..."
line 139, delete "as"
line 145, instead of "at analysis" (not wrong, just uncommon) maybe use "in the analysis"
In the paragraph beginning in line 153 I see an uncommon multiple use of the colon character ":" as a delimiter inside the phrase.
The intention is fine, and a version with only commas "," may seem awkward, too. Leave that to the desk editor ...
line 188, "an example", " by the 'shooting' "
line 211, "has not mathematical difficulties"? This is incorrect English; "has no mathematical difficulties" may be too strong,
"does not pose serious mathematical difficulties" may be what the author wants to say.
line 215, the conditions suggests a low initial charge number; the lowest I can think of is not 1, but 0, for neutral beam injection.
Maybe the author could mention this option (with its own set of problems)
and why it is not part of the present discussion - and be done with it.
Here the daring schemes of HIBP begin in earnest, and the author's language shows his involvement. Very good.
line 380, figure caption, "azimuthally"
line 395, "stricture" or "structure"?
line 759, "in the early 2000th" is un-English; early in the 21st century, early in the 2000s, ... ?
The long list of historic experiments and newer developments is a welcome review of this sector of the plasma diagnostics
activities. As happens so often, the interested scientists' hopes are not all funded (e.g. at ITER), but when the researchers
manage to provide a device for helping with development and operations safety, they may find that they can
gather science data after all. Good luck!
Author Response
Author is deeply grateful to Referee 1 for the careful reading of the manuscript and giving very positive remarks and suggestion for improvement.
Author Response File: 
Author Response.docx
Reviewer 2 Report
The manuscript contains an extensive review of the Heavy Ion Beam probing (HIBP) technique for the diagnosis of the core of thermonuclear plasmas, written by a leading expert in the subject.
The work is structured with a first part that describes the basic physical principles of the HIBP as well as the mathematical machinery needed for the interpretation of the experimental results. Then, the author provides an impressive overview of the results achieved with HIBP diagnostics at the several tokamaks and stellarators throughout the world where it has been deployed. The only small deficiency which I could spot is the lack of a paragraph devoted to physics results obtained in reversed field pinch and mirror machines, which were mentioned in the Introduction; but it does not affect the overall validity of the study.
Section 8, eventually, provides engineering and conceptual designs of the diverse HIBP diagnostics, both existing and in construction.
I found the manuscript excellently written and informative. It can be published in the present form.
I point out just two minor details:
1. In the discussion around Eq. (4) and (5) the author refers exclusively to HIBP using Caesium ions. It seems a bit limiting, in view of the fact that the discussion appears referring generically to any kind of probe ion, and just few lines above the author had stated that several elements are used.
2. There must be some problem with the fonts in Eq. (20). The left hand side should read Gamma_{ExB), but in my copy the lowerscript is unintellegible.
Author Response
Author is deeply grateful to Referee 2 for the careful reading of the manuscript and giving very positive remarks and suggestion for improvement.
Author Response File: Author Response.docx
