Peer review of: Evidence of ubiquitous Alfvén pulses transporting energy from the photosphere to the upper chr (2019)


RR3

Reviewers' comments:
Reviewer #2 (Remarks to the Author):
I quickly check the revised version, especially for
the part I recommended to revise, and found that
the authors revised and added the negative results honestly on the relation between swirls and vertical magnetic flux tubes because of lack of spatial resolution of HMI
in supplementary material.
Then the reader can check the reliability of the paper on the basis of these results.
Hence I now recommend publication of this paper in the present form.
Reviewer #3 (Remarks to the Author):
The authors have addressed some of my comments of the previous report. However, a couple of serious concerns remains.
The authors claim that the Alfven pulses propagate upwards through the solar atmosphere carry 1.9- 7.7kW/m^2 energy flux and now compare it to the average loss of quiet chromospheric regions of 0.1kW/m^2. In the present version paper and in previous version the authors have calculated the average energy flux carried by these waves is 0.033-0.131 kW/m^2 (line 84 of the supplement), and the average flux is more appropriate value to compare to the average quiet chromospheric losses. I find the present description misleading in that one has to look carefully in the supplement in order to identify the relevant energy flux that may balance chromospheric losses. Also, it is still not evident

in the present study whether enough wave energy flux is actually dissipated to provide the required heating.
The authors use the WKB approximation in order to estimate the wave energy flux (equation S3). The WKB approximation neglects reflection and dissipation in the calculation of the energy flux. Thus, the energy flux could be in fact much lower, if one accounts for the above effects. This should be clearly noted and discussed in the supplement.
In summary, given the estimated marginal energy flux provided by the Alfven pulses for chromospheric heating, and still uncertain effects of dissipation and reflection in the present study, I am not convinced that the claims made in the paper are more than speculative, and of interest to the general scientific community. Therefore, I still cannot recommend publication in Nature Communications.
Independent reviewer's remarks to the author:
I would be happy if the authors can explicitly state the limitations raised by Reviewer 3 in their manuscript. In particular,
Regarding the comment:
- I find the present description misleading in that one has to look carefully in the supplement in order to identify the relevant energy flux that may balance chromospheric losses. Also, it is still not evident in the present study whether enough wave energy flux is actually dissipated to provide the required heating.
The authors should shortly discuss this in the main text.
Regarding the comment:
The authors use the WKB approximation in order to estimate the wave energy flux (equation S3). The WKB approximation neglects reflection and dissipation in the calculation of the energy flux.

Thus, the energy flux could be in fact much lower, if one accounts for the above effects. This should be clearly noted and discussed in the supplement.
The authors should explicitly mention this limitation in the supplement.