Review Editor Subject: Structure and Evolution of Magnetic Fields Associated 2014-12-20 with Solar Eruptions 12:48 PM I found that the paper is carefully written and very interesting For author and timely. It will encourage and help the Chinese young students and editor and colleagues to work in this important working area. I tentatively list a few minor comments and suggestions for the authors’s consideration.

1. In the abstract, you mention “the rapid response of photospheric magnetic field to eruptions”. I feel it is better using observational term here, like somehow ‘the rapid changes during (or in the course of ) the eruption’. Since the response to eruptions would imply the physics which may need more supporting from both observational and theoretical investigations. You may mention the idea about the response in the main text, but better not in the abstract.

2. In page 4, the name of NAOC is “National Astronomical Observatories of Chinese Academy of Sciences”.

3. In the same page, the “surface magnetic free energy” was first used by Wang et al. (1996), Leka & Barnes (2003, 07) cited and only adopted the parameter for their statistical studies. Regarding to the vector field parameters, may I suggested you to kindly refer a paper by Chen and Wang (2012, A&A, 543, A49), which used four vector field parameter and quoted your paper about field gradient? Another suggestion is if you may like to mention the paper of Hagyard et al. (1984), the first paper on the quantitative description of magnetic shear. She was the first.

4. Page 6, “tracking November & Simon …”, missed a word ‘by’ or a ‘,’.

5. Page 9,”E.g. Sterling…”, should be ‘e.g. …’?

6. Page 12, about helicity. You mentioned “an important parameter to characterize magnetic non-potentiality”. It may not be accurately true, since (1) the potential field has helicity, (2) The real importance of magnetic helicity is to specify how much free energy could be released during the reconnection or topology collapse, see if H=0 always then the minimum energy state is the potential field; if the dH/dt=0 always, then the minimum energy state is a constant force-free field (the above two rules have been approved); if the magnetic connectivity does not change (a kind of constraint of helicity), then the minimum energy state is speculated to be non-constant force-free field. In this way, helicity specifies how much free energy can be released. It represents magnetic complexity. Like for a twisted string, if the connectivity is reserved, then only a little of free energy can be released by adjusting the configuration; only by cutting the string and having the helicity reduced to 0, more or all the twisted mechanical energy could be released. I mentioned the above idea somewhere in a paper, which I do not remember exactly, possibly in my 1999 review entitled Vector magnetic field and magnetic activity on the Sun in Fundamental of Cosmic Phys, or partially mentioned in Wang et al (2004) paper. For the magnetic non-potentiality, the (photospheric) surface free energy density (or ‘source field’, by Hagyard, Low, and Tandburg-Hansen, 1991?) already gives a complete description.

7. Page 25, “collapse toward the surface”. Could we open another possibility, i.e. the sudden release of flux rope from below to the surface, which triggers the immediate eruption? For the late case, I have no idea if the temporal evolution is consistent with observations, as I have not worked as much as you and your colleagues have done. I mentioned this possibility in my 2009 ApJ paper, since we saw the flux rope staying in the surface without eruption but strengthened, during which flare/CME took place.

8. Page 27, would you pleas mention the techur-cutting model is still of the phenomenological nature. It was not a physical model. It would be good for younger colleagues for an accurate understanding.

9. In the same page, “a two-step reconnection” idea was first proposed by Wang and Shi (1993). Other colleagues, e.g., Shibata (2005) commended that either techur-cutting or other models can be classified into Wang & Shi two-step reconnection model. I like to mention this, but you may not necessarily mention it.

10. Page 33, “circular-like ribbon…” is not a new revelation. In 1980s my classmate, Zhengzhi Wang and Professor Lin Yuanzhang already studied circular flare with a paper published in Science China. You may use ‘described with …’ instead.

Editor/Author Correspondence Editor Subject: [RAA] MS 2113: Your article has been accepted for 2014-12-22 Research in Astronomy and Astrophysics 05:57 PM Ref: RAA/MS 2113

Dear Haimin Wang,

MS #:2113 Title: Structure and Evolution of Magnetic Fields Associated with Solar Eruptions Author(s): Haimin Wang, Chang Liu

We are pleased to inform you that the above article has been accepted for publication in Research in Astronomy and Astrophysics. Correspondence concerning the logistical aspects of publishing this manuscript should be directed to raa@raa- journal.org. If you have any additional questions concerning the scientific content of your manuscript, please direct them to me.

Sincerely Yours,

Prof. Jingxiu Wang National Astronomical Observatories, CAS, Beijing Phone +86-10-64888720 [email protected] Scientific Editor Research in Astronomy and Astrophysics