Electrostatic Shock Structures in a Magnetized Plasma Having Non-Thermal Particles

Round 1

Reviewer 1 Report

In this manuscript, the authors investigate the nonlinear dynamics of dust-ion-acoustic (DIA) shock waves in a magnetized plasma composed of inertial warm positive and negative ions, inertialess non-thermal electrons and positrons, and static negatively charged massive dust grains. The method is quite standard and is based on the reductive perturbation technique. The overall paper is well-written and the results are sound and may be of interest for the plasma physics or astrophysics communities. Hence, the paper is worth (at least in principle) a publication in Gases. I have one suggestion that may improve the quality of the manuscript. The authors provide a number of references that support the existence of non-thermal populations in different observations. I would like to draw the authors' attention to some recent formal results in the statistical mechanics literature that also give a statistical justification to the Cairns nonthermal justification (see for instance Eq. (21) in [Physica A 322, 267 (2003]; Eq. (11) in [Phys. Rev. E 91, 012133 (2015)] and also [Phys. Rev. E 100, 023205 (2019); Phys. Rev. Research 2, 023121 (2020).]) These results seem to indicate that nonthermal distributions emerge as a consequence of thermal fluctuations, which support the work of the authors since many plasma environments where collisional events are rare (eg., in the solar wind), are subject to thermal fluctuations.

Author Response

RESPONSE TO REVIEWER 1

Point 1.

Suggestion: ''In this manuscript, the authors investigate the nonlinear dynamics of dust-ion-acoustic (DIA) shock waves in a magnetized plasma composed of inertial warm positive and negative ions, inertialess non-thermal electrons and positrons, and static negatively charged massive dust grains. The method is quite standard and is based on the reductive perturbation technique. The overall paper is well-written and the results are sound and may be of interest for the plasma physics or astrophysics communities. Hence, the paper is worth (at least in principle) a publication in Gases. I have one suggestion that may improve the quality of the manuscript. The authors provide a number of references that support the existence of non-thermal populations in different observations. I would like to draw the authors' attention to some recent formal results in the statistical mechanics literature that also give a statistical justification to the Cairns nonthermal justification (see for instance Eq. (21) in [Physica A 322, 267 (2003]; Eq. (11) in [Phys. Rev. E 91, 012133 (2015)] and also [Phys. Rev. E 100, 023205 (2019); Phys. Rev. Research 2, 023121 (2020).]) These results seem to indicate that nonthermal distributions emerge as a consequence of thermal fluctuations, which support the work of the authors since many plasma environments where collisional events are rare (eg., in the solar wind), are subject to thermal fluctuations''.

Response 1: We have included the recommended references in our revised manuscript (please see Refs. [41-44]).

Author Response File: Author Response.pdf

Reviewer 2 Report

See attached report

Comments for author File: Comments.pdf

Author Response

RESPONSE TO REVIEWER 2

Suggestions and response:

Point 1. ''What is the reasoning behind the numerical values chosen as mentioned in lines 152-153 (numerical analysis part) for different plasma parameters used in the manuscript? Are these parameters supported by the literature or experiments?''

Response 1: To incorporate this suggestion, we have included a few lines in the first (lines 150 to 153 of page 7) and third (lines 183 to 194 of page 8) paragraph and associated figure (the right panel of Fig. 4) of section 4. We note that the parameters used are also available in our earlier researches (kindly see the references [8, 10, 13-16, 26, 29, 54, 55]).

Point 2: Authors should give more physical interpretation for the obtained results. For example, in Fig (2) to Fig. (7), there is only one single line is written which shows that shocks amplitude is increasing/ decreasing with increasing/decreasing values of various plasma parameters. What is physically happening in the system, explain in detail?

Response 2: The viscous force acting in positive and negative ion fluid of the plasma model under consideration is the source of dissipation, and is responsible for the formation of shock structures [50] displayed in Figs. (1)-(4). Please see the lines (147-150) of page 7 of section 4 and also see the lines (130-135) of page 5 of section 3.

Point 3: There are some typos.

Response 3: We have read our manuscript very carefully few more times, and to correct all grammatical and typographical errors throughout the manuscript.

Author Response File: Author Response.pdf

Reviewer 3 Report

A series of flaws arise in this interesting manuscript.

1-After equation 5, equations were introduced in a messy way inside the paragraph.

2-Section 2 requires more organization. Equations are not well explained.

3-Burger's equation is not well introduced and why its emergence in the present work.

4-The negative regions in all graphs must be justified, i.e. the asymptotic tail.

5-Some references are missed: Physics of Plasmas 18, 052308 (2011); Plasma 2021, 4, 426–434. https://doi.org/10.3390/plasma4030031; Adv. Space Phys. 61, 2914-2931 (2018); Proc. R. Soc. A476, (2020) Article ID:20200190 https://doi.org/10.1098/rspa.2020.0190; Theor Appl Phys 10, 289–296 (2016). https://doi.org/10.1007/s40094-016-0228-6; Res. Phys. 12, 2164-2168 (2019)

 

Author Response

RESPONSE TO THE REVIEWER 3

Suggestions and responses:

Point 1: After equation 5, equations were introduced in a messy way inside the paragraph

Response 1: We have carefully re-organized our all equations in our revised manuscript.

Point 2: Section 2 requires more organization. Equations are not well explained.

Response 2: We have rewritten our section 2.

Point 3: Burger's equation is not well introduced and why its emergence in the present work.

Response 3: It is well established that the ion fluids are viscous and in realistic situations, ion fluids which occurs in both space [50] and laboratory [50, 51] plasmas, where the effect of viscous force can not be neglected. It is important to note here that the Burger's equation defined by Eq. (38) derived for our multi-ion dusty plasma system, when the effect of dispersion is negligible compared to that of dissipation (please see the lines of 130-135 of page 5). Also kindly see the lines of 147-150 of page 7.

Point 4: The negative regions in all graphs must be justified, i.e. the asymptotic tail.

Response 4: To answer this, we have included a new paragraph (lines 195 to 203 of page 8) and associated figure (Fig. 5) in section 4.

Point 5: Some references are missed: Physics of Plasmas 18, 052308 (2011); Plasma 2021, 4, 426–434. https://doi.org/10.3390/plasma4030031; Adv. Space Phys. 61, 2914-2931 (2018); Proc. R. Soc. A476, (2020) Article ID:20200190 https://doi.org/10.1098/rspa.2020.0190;
Theor Appl Phys 10, 289–296 (2016). https://doi.org/10.1007/s40094-016-0228-6; Res. Phys. 12, 2164-2168 (2019)

Response 5: We have included the recommended references in our revised manuscript (please see Refs. [38-39, 45-47, 56]).

Author Response File: Author Response.pdf