On the ion-inertial-range density-power spectra in solar wind turbulence

Treumann, Rudolf A.; Baumjohann, Wolfgang; Narita, Yasuhito

doi:https://doi.org/10.5194/angeo-37-183-2019

Articles | Volume 37, issue 2

https://doi.org/10.5194/angeo-37-183-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/angeo-37-183-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 37, issue 2

ANGEO Communicates

|

03 Apr 2019

ANGEO Communicates |

| 03 Apr 2019

On the ion-inertial-range density-power spectra in solar wind turbulence

Rudolf A. Treumann, Wolfgang Baumjohann, and Yasuhito Narita

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Final revised paper (published on 03 Apr 2019)
Preprint (discussion started on 05 Dec 2018)

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

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- Supplement

RC1: 'Suggestions for improvement', Anonymous Referee #1, 02 Jan 2019
- SC1: 'Thanks', Rudolf Treumann, 04 Jan 2019
- AC1: 'Final Response', Rudolf Treumann, 11 Feb 2019

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

ED: Publish subject to revisions (further review by editor and referees) (20 Feb 2019) by Elias Roussos

Dear Prof. Treumann,

thank you for submitting your article «On the ion-inertial range density power spectra in solar wind turbulence» to Annales Geophysicae, for responding in such great detail to the reviewer's comments and for providing an early view of your revised manuscript. The reviewer finds your study both interesting and timely, remarking mostly on aspects of presentation and lack of references to relevant past works. I am therefore positive in publishing your work in our journal, however a formal acceptance for publication may only come following a review of your manuscript's revision.

After studying the interactive discussion, I understand that the extensive answers you provide, along with the draft of the revised manuscript, answer to all concerns raised by the reviewer. It was not always clear to me when the reviewer was just asking for clarifications in the open discussion or a major rewriting of manuscript parts, but nevertheless the major revision you provide accounts for any of the two possibilities.

To the level I can understand the details of your manuscript, I am satisfied with the revision's early view version, so I invite you to submit it as your final revised article, along with the answers to the reviewers already provided in the discussion. Any additional changes you may still want to do, that are not included in your replies in the Interactive discussion, are of course possible. Independent of further changes, I would still send your revision to the referee for another round of review, due to the many changes done compared to the original version.

I am looking forward to receiving your revision,

Kind regards,

Elias Roussos

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AR by Rudolf Treumann on behalf of the Authors (21 Feb 2019) Author's response Manuscript

ED: Referee Nomination & Report Request started (22 Feb 2019) by Elias Roussos

RR by Anonymous Referee #1 (03 Mar 2019)

Suggestions for revision or reasons for rejection

I thank the authors for the very detailed response to all of my comments and for the very extensive rewriting of their manuscript. I sincerely was actually not expecting that. I just suggested some small clarifications to make the manuscript more understandable for a wider audience. In addition, I did not consider that they were many fundamental clarifications other than the unclear writing of some sentences (sorry if I was too pedantic with that). Other readers may have misunderstood the point of this paper in the same way as I. So, I sincerely apologize for all the additional work that my suggestions involuntarily caused to the authors.

In my opinion, the revised version of the manuscript now is more clear than before.
The organization of the different sections into subsections makes everything easier to follow.
In particular, the last paragraph of page 4 (part of the introduction): I think this is one of the most important addition of the revised version of this manuscript, which explains its main point and purpose, what makes this manuscript different from other approaches explained in the previous paragraph (in page 3). The last paragraph in page 3 also motivates very well the purpose of this paper in explaining the observed bumps in the turbulent spectra. The description written in the second paragraph in page 4 is quite helpful to understand the motivation behind the idea presented in this paper. The same goes for the very helpful first paragraph in page 17 (section 5, discussion).

I have only a few small comments and possible typos to be corrected, actions items that it would be good to address before publication, please. All of them are only related with the new additions/corrections of this version of the manuscript and should not require to change more than a few words/one sentence each. This is just to try to make the manuscript more precise, please.

------------------------------------------------------
REMARKS:

1) page 4 "If kinetic Alfvén waves are unambiguously confirmed, the inner solar wind ... must be subject to the continuous presence of small scale collisionless shocks" ---> This is a strong statement, which requires more evidence, otherwise it would be misleading. Why the "must"? I am not sure if that is the only possible choice, the presence of KAWs could be associated to shocks, but I think it is not strictly required.

2) (possible typo) page 5: "particles "loose" their magnetic property" ---> shouldn't be "lose" instead of "loose"?

3) page 9, Figure 2: The region below the solid line "Te/Ti=1" should be generally forbidden" In what sense is "forbidden"? (it could happen anyway, see also remark 3)

4) page 9, I have some concerns about the sentence "However, the temperature ratio Te /Ti is variable and usually large, varying between a few and a few tens". And in Fig 2: "In the solar wind the temperature ratio is usually between the solid and dashed lines but mostly closer to the dashed, depending on the exact value of beta_e" (dashed line is Te/Ti=10).
I am not sure about the validity of that statement.

According to
"Newbury, J. A., Russell, C. T., Phillips, J. L., & Gary, S. P. (1998). Electron temperature in the ambient solar wind: Typical properties and a lower bound at 1 AU. Journal of Geophysical Research: Space Physics, 103(A5), 9553–9566. https://doi.org/10.1029/98JA00067"
the ratio Te/Ti tends to be mostly between 4 and 0.5.

And "Wilson III, L. B., Stevens, M. L., Kasper, J. C., Klein, K. G., Maruca, B. A., Bale, S. D., … Salem, C. S. (2018). The Statistical Properties of Solar Wind Temperature Parameters Near 1 au. The Astrophysical Journal Supplement Series, 236(2), 41. https://doi.org/10.3847/1538-4365/aab71c"
found that the typical temperature ratio in the solar wind is actually Te/Ti=1.64 , with a standard deviation of 1.27. So, values even close to Te/Ti=10 are actually rare, and not really a few tens.
Any comment or clarification, please?

5) (typo) page 13: "with a factor of proportionality ........ ()1/3". I think the factor (1/3) should be the exponent of the parenthesis (not multiplied as it is now).

6) (possible typo) page 16, Table 1. In the second row, last column, shouldn't be -1/3 instead of -1/6?
(I noticed than the spectral indices ("a-2") are corrected compared to the previous version (I overlooked them before) and also that one table was removed, probably it was not needed. It is also clearer the last column with an explicit b/2 instead of c.)

7) page 19: "the power in the second to last expression becomes 1/3" ---> which equation this is referring to? Eq. (43)? If so, which exponent exactly?

8) page 27, Caption Figure 3: "power spectrum exhibits a so-called bump at intermediate frequencies of positive slope ~\omega^{1/3}" But later, "The large scatter in the data (weight of line) inhibits distinguishing between K and IK inertial range velocity turbulence" (and similar statements in the main text). So, that sounds like a contradiction, it should be written in the caption that the fit could be both \omega^{1/2} and \omega^{1/3} (not only the latter).
Similar for Figure 4. "The positive slope \omega^{1/6} in the deformation confirms its origin from pressure balance" I think both slopes 1/6 and 1/4 work as a fit.

9) (typo) page 21, "Sine both evolve" --> "Since both evolve"

10) page 21: "Moreover, from the observations the total \beta > 1 though nothing is known about \beta_i. We expect \rho_i > \lambda_i, and also \beta_i~1" This is a contradictory sentence, either beta_i is known or not.

11) page 21: please mention what V_0 and U_0 are in the first line of the summary and outlook, that will make this section more self-contained (or at least please make a cross-reference to their definitions after Eq 2 in page 6).

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ED: Publish subject to minor revisions (review by editor) (13 Mar 2019) by Elias Roussos

AR by Rudolf Treumann on behalf of the Authors (14 Mar 2019) Author's response Manuscript

ED: Publish as is (20 Mar 2019) by Elias Roussos