Interaction of Ultrashort Laser Pulses with Atoms in Plasmas
Round 1
Reviewer 1 Report
Reviewer comments
Manuscript ID: atoms-320206
Type of manuscript: Article
Title: INTERACTION OF ULTRASHORT LASER PULSES WITH ATOMS IN PLASMAS
Authors: Valeriy Astapenko *, Valery Lisitsa
Sp.Issue: Stark Broadening of Spectral Lines in Plasmas
https://www.mdpi.com/journal/atoms/special_issues/stark_broadening_plasmas
In this paper authors present their investigation of absorption of ultrashort laser pulses on atoms in plasmas with account for different broadening mechanisms of atomic resonant transitions. The results are presented by dimensionless parameters. Obtained results are important for the laboratory and other research.
The manuscript is interesting for potential readers. But it is necessary to make some corrections and improvement of the paper.
Some requests:
The main defect of the text is the lack of comparison with the results of other authors. If there are no in the existing literature it would be desirable that, at least the authors describe the current situation in this field and the specify what problems arise during their investigation. This would indicate the reason for accepting this work and it will be good for potential readers.
Also, in this context it would be good if the authors describe a little bit about the importance of this investigation in the laboratory research and some applications.
First sentence in Sec. Introduction, typo:
“The progress in generation of utrashort …” => “The progress in generation of ultrashort …”
Last sentence in page 1. “ The structure of the paper is as following: n.2 contains general formulas for USP absorption line shape presented in terms of universal broadening parameters, n.3 is devoted to the application of general …” =>
“The structure of the paper is as following: Section 2 contains general formulas for USP absorption line shape presented in terms of universal broadening parameters, Section 3 is devoted to the application of general …”
Generally, all figures are of poor quality. It's like they're cut off from some text. Especially Figure 2.
Page 9, bottom: In Author Contributions please insert missing text or remove template text.
In References:
all references should be written in the same way, according to the journal
style.
- In some refs. authors use full journal name and on some abbreviation. They
should be written in the same way.
also
in my opinion authors should expand the list of references. For ten pages paper, 7 Refs. is not enough even for the Intro.
Respectfully,
Author Response
Some requests:
The main defect of the text is the lack of comparison with the results of other authors. If there are no in the existing literature it would be desirable that, at least the authors describe the current situation in this field and the specify what problems arise during their investigation. This would indicate the reason for accepting this work and it will be good for potential readers.
Also, in this context it would be good if the authors describe a little bit about the importance of this investigation in the laboratory research and some applications.
The reply to the above reviewer requests is contained in the following insertions in the Introduction. See also other insertions in the Introduction.
The interaction of USP with atomic systems is of large interest for plasma investigations. The long laser pulses in standard diagnostics (fluorescence schemes) deal usually with excitation of radiative transitions between excited atomic states which belongs to the visible spectral range. The contrast of fluorescence signal in the case is rather small because the populations of excited atomic levels are not so different under standard plasma conditions. At the same time the carried frequency of USP is often in the ultraviolet or even X-ray spectral range making it possible the excitation of atoms and ions in plasmas from their ground states. In the case the observed fluorescence signal grows many orders of magnitude due to the large populations of ground states. This opens new possibilities for plasma diagnostics, see the discussions in [4].
First sentence in Sec. Introduction, typo:
“The progress in generation of utrashort …” => “The progress in generation of ultrashort …”
It seems to be identical
Last sentence in page 1. “ The structure of the paper is as following: n.2 contains general formulas for USP absorption line shape presented in terms of universal broadening parameters, n.3 is devoted to the application of general …” =>
“The structure of the paper is as following: Section 2 contains general formulas for USP absorption line shape presented in terms of universal broadening parameters, Section 3 is devoted to the application of general …”
It is done
Generally, all figures are of poor quality. It's like they're cut off from some text. Especially Figure 2.
It is done
Page 9, bottom: In Author Contributions please insert missing text or remove template text.
This item is not clear
In References:
all references should be written in the same way, according to the journal
style.
It is done
- In some refs. authors use full journal name and on some abbreviation. They should be written in the same way.
It is done
Also in my opinion authors should expand the list of references. For ten pages paper, 7 Refs. is not enough even for the Intro.
Three additional references [2, 4, 10] are inserted in the text
Reviewer 2 Report
The manuscript „Interaction of ultrashort laser pulses with atoms in plasmas“ by V.A. Astapenko and V.S. Lisitsa deals with different broadening mechanisms of atomic resonant transitions. The analysis is made in terms of absorption probability, investigating pulse duration and carrier frequency.
Although the content is clearly presented, several issues have to be improved before recommending the paper for publication.
1) In the introduction the authors use ultrashort electromagnetic pulse (USP) synonymous for X-ray pulses from a free electron laser in contrast to ultrashort laser pulses in the visible spectral range. This confuses, since this is clarified one sentence behind USP. It is neither mentioned in the title of the manuscript nor the abstract. It would help a lot to modify the title to “Interaction of ultrashort X-ray pulses with atoms in plasmas”.
2) There are no “standard laser pulses”, use instead “femtosecond laser pulses”.
3) References [1] and [2] deal with pulses from FEL (large amount of photons, (sub-)femtosecond pulses) and attosecond pulses from HHG (low amount of photons, tens of attoseconds). It is hard to guess the relevance for both experimental conditions due to universal dimensionless parameters (since W(alpha, delta) is proportional to E_0^2 and alpha^2). The authors should add in the introduction a few sentences about possible experimental conditions and perhaps some references.
4) In the introduction, the structure of the paper contains wrong formatted links to the sections of the paper. And the is a spelling mistake “Vogt” instead of “Voigt”.
5) The General Formulas start with a large gap between text and formula (1).
6) All the figures look pixelated. The authors should improve the resolution of the figures.
Author Response
Although the content is clearly presented, several issues have to be improved before recommending the paper for publication.
1) In the introduction the authors use ultrashort electromagnetic pulse (USP) synonymous for X-ray pulses from a free electron laser in contrast to ultrashort laser pulses in the visible spectral range. This confuses, since this is clarified one sentence behind USP. It is neither mentioned in the title of the manuscript nor the abstract. It would help a lot to modify the title to “Interaction of ultrashort X-ray pulses with atoms in plasmas”.
The reply to the above reviewer requests is contained in the following insertions in the Introduction. See also other insertions in the Introduction.
The USP can be used for plasma investigations both in X-ray and visible spectral ranges. The X-ray pulses providing by XFEL are useful for investigations of high temperature dense plasmas where the radiative transitions in atomic systems such as highly charged ions belong to X-ray spectral range. At the same time the USP in the visible spectral range can be applied for investigations of low temperature plasmas where radiative transitions in neutral atoms (for example alkali atoms, etc) are just in visible spectral range. The expressions for radiative transitions probabilities in the paper are expressed in terms of universal functions making it possible their application for both cases pointed above. Moreover such universal representation opens possibilities to transfer the results of specific investigations to other conditions following the dimensionless parameters of the consideration.
2) There are no “standard laser pulses”, use instead “femtosecond laser pulses”.
It is done.
3) References [1] and [2] deal with pulses from FEL (large amount of photons, (sub-)femtosecond pulses) and attosecond pulses from HHG (low amount of photons, tens of attoseconds). It is hard to guess the relevance for both experimental conditions due to universal dimensionless parameters (since W(alpha, delta) is proportional to E_0^2 and alpha^2). The authors should add in the introduction a few sentences about possible experimental conditions and perhaps some references.
To answer this question the following paragraph is inserted in Introduction
The consideration is made in the frame of first order perturbation theory with respect to pulse amplitude E0. So the absorption probability is proportional to the squared product of E0 and pulse duration t. Thus the probability is quite different for XFEL and HHG pulses. The specific example is considered in the paper [10].
4) In the introduction, the structure of the paper contains wrong formatted links to the sections of the paper. And the is a spelling mistake “Vogt” instead of “Voigt”.
It is done.
5) The General Formulas start with a large gap between text and formula (1).
It is done.
6) All the figures look pixelated. The authors should improve the resolution of the figures.
It is done.
Round 2
Reviewer 1 Report
Only two minor corrections left (this can be corrected in the proof).
In the revised manuscript the authors missed to correct typo (line 25 utrashort => ultrashort) and omit to give proper “author contribution”.
