Estimates of Isotope Ratios in the Magnetosphere and Implications for Implantation of Atmosphere in Lunar Regolith

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

In this paper the authors use spacecraft data and modeling techniques to estimate te ion isotope ratios and provenance in the earth's upper ionosphere. The paper is well written and the methodology and results are sound given the sparsity of data and lack of overall knowledge in the community. My own specialty is space physics, not chemistry, but I can make some comments / suggestions, as follows:

1) Temperature profile used for the study in figure 2 seems too simple (1973 paper). Why not use the IRI model or NRLMSISE model temperature profiles? These are more up to date and take into account the latest measurements.

2) Night time and day time isotope variations should be contrasted, or please mention why they do not matter.

3) As a follow on to the previous remark, what are the expected seasonal variations, or is it not possible to comment on this?

4) A very important quantity for space physics researchers is inter-species collision frequencies which yield valuable information about conductivities and flows of the plasmas. Could the authors suggest how isotope studies could contribute to this aspect?

4) I believe above 1000 km electron precipitation during geomagnetic events may have a large impact on the results. Can the authors comment on this?

Author Response

 Thank you very much. Please kindly consider the attached file.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

In this study, the authors address an important problem regarding the plasma in the Earth's magnetosphere and draw attention to a dimension that has rarely been studied in the literature, with evaluations made on the isotope ratios of ions. The problem is quite current in terms of both space plasma physics and interplanetary matter transport. The study offers significant implications on how isotope ratios can be used, especially in the separation of polar wind and solar wind sources. In this sense, the use of isotope ratios can be presented as a new perspective. The reference that originates the model is quite strong (Chappell et al. 1987). The comparison made in the study supports the reliability of the model.

The anonymous reviewer considers that the authors have presented the reader with a study that can contribute to the literature.
It is meaningful to mention a few discussions:

A short but clear statement about the general framework of the method in the abstract and conclusion sections will help the reader understand the study better. For example: A short sentence like "Using a diffusive equilibrium model with source fluxes adapted from Chappell et al..."

Although the conclusion is rich in content, some paragraphs are presented in a combined form. The discussion of the Moon could be separated from the modeling findings and given in a separate paragraph. This would make it easier for the reader to digest the different findings.

The proposal for measuring deuterium is valuable, but technical obstacles such as low abundance and mass overlap could be expressed more simply or supported by explanatory notes.

The scientific impact should be emphasized more strongly.

Author Response

 Thank you very much. Please kindly consider the attached file.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

 The authors estimated isotope ratios for several light ions (H+, He+, N+ and O+) in the magnetosphere. They concluded that the primary source of N and O magnetospheric ions is the polar wind, and He ions come primarily from the solar wind. H ions come from both polar and solar winds. Moreover, the extreme diffusive separation of O+ isotopes argues against the polar wind as a significant source of O to the lunar regolith during passage of the Moon through the magnetotail.

The manuscript is well written, and it may be published after a minor revision.

 

1) Figure 7, do the bars represent the std? it should be introduced.

2) The conclusions may be simplified, focusing on the most significant results.

Author Response

 Thank you very much. Please kindly consider the attached file.

Author Response File: Author Response.pdf