the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 21 Oct 2025
Earth’s magnetosheath: A comparison of plasma flow direction between models and observations
Abstract. Observations of the plasma flow direction in the Earth’s magnetosheath are compared with the help of three analytical magnetic-field models, namely Kobel and Flückiger (1994), Romashets and Vandas (2019), and Vandas and Romashets (2019), which all assume current-free fields in the magnetosheath. 47 magnetosheath passages by spacecraft are analyzed in detail and performance of the models are evaluated. It is concluded that the performances are comparable and that they are satisfactory on average. Therefore, a usage of the model by Kobel and Flückiger (1994) is recommended, because it is the simplest one and yields results much faster.
- Preprint
(695 KB) - Metadata XML
- BibTeX
- EndNote
Status: open (until 17 Dec 2025)
-
RC1: 'Comment on egusphere-2025-4672', Anonymous Referee #1, 02 Nov 2025
reply
-
AC1: 'Reply on RC1', Evgeny Romashets, 02 Nov 2025
reply
We thank the referee for the valuable comments and suggestions.
We shall incorporate them into a revised version.Citation: https://doi.org/10.5194/egusphere-2025-4672-AC1
-
AC1: 'Reply on RC1', Evgeny Romashets, 02 Nov 2025
reply
Viewed
| HTML | XML | Total | BibTeX | EndNote | |
|---|---|---|---|---|---|
| 126 | 23 | 11 | 160 | 6 | 3 |
- HTML: 126
- PDF: 23
- XML: 11
- Total: 160
- BibTeX: 6
- EndNote: 3
Viewed (geographical distribution)
| Country | # | Views | % |
|---|
| Total: | 0 |
| HTML: | 0 |
| PDF: | 0 |
| XML: | 0 |
- 1
Referee Report on EGUsphere Preprint 2025-4672 entitled “Earth’s magnetosheath: A comparison of plasma flow direction between models and observations”
This is a simple, yet interesting, paper that compares observations of magnetosheath magnetic fields and plasma flow directions with the predictions of simple analytical models for these parameters. The paper will eventually be suitable for publication, but there are some important tasks to be completed before it can be published.
The first task is to properly reference past research. Both Howe and Binsack (JGR, 77, 3334, 1972) and Crooker et al. (JGR, 89, 9711, 1984) have compared flow directions within the magnetosheath with theoretical and model predictions. They are not referenced in the present paper.
The present paper finds discrepancies between observed flows and model predictions, particularly in the vicinity of the magnetopause, but makes no attempt to explain why this might be the case. The authors should consider the various predictions described by Crooker et al. and see if these help explain their results.
The authors scale magnetopause and bow shock positions by the solar wind dynamic pressure, but they must surely be aware that magnetic reconnection and erosion cause the magnetopause (and therefore the bow shock) to move inward during periods of southward IMF orientation. They should note that they are ignoring this effect near line 73.
The authors tell where the bow shock and magnetopause shapes come from for Magnetic field model 2 and 3, but there is no statement about this for Magnetic field model 1 in the vicinity of line 80.
In Section 3, the authors report that they require bow shock and magnetopause crossings to be clearly identifiable, but they do not tell what they do when there are multiple magnetopause and bow shock crossings. Which one do they choose?
The authors shift solar wind observations to the bow shock nose, but how do they shift them to match spacecraft observations further downstream? Some of the intervals in Table 1 occur near the terminators.
Could the authors please comment on what the typical cause of high delta? Is it a poor prediction for the flow direction in the Y-Z plane or a poor predictions of VX?
Successful prediction of magnetosheath parameters may depend on the location of the solar wind monitor. Monitors far off the sun-Earth line may not see the features that reach Earth. Can the authors please present the dependence of delta on the distance of the solar wind monitor from the Sun-Earth line?
Reconnection at the magnetopause may affect plasma flow patterns in the magnetosheath. Could the authors please present the dependence of delta on the north/south component of the IMF orientation?
Magnetic fiield directions and strengths may be more important in the magnetosheath when the solar wind Mach number is low. Could the authors please present the dependence of delta on the solar wind Mach number?
The dashed line ‘fits’ to the point in each panel of Figure 6 are not very compelling. The authors should provide the correlation coefficients for each fit.
It would be good if the authors make an effort to explain why the discrepancies between observed and predicted flow direction are greatest in the subsolar magnetosheath for large cone angle.