# Beyond the random phase approximation: Stimulated Brillouin backscatter for finite laser coherence times

## Abstract

We developed a linear theory of backward stimulated Brillouin scatter (BSBS) of a spatially and temporally random laser beam relevant for laser fusion. Our analysis reveals a new collective regime of BSBS (CBSBS). Its intensity threshold is controlled by diffraction, once cT{sub c} exceeds a laser speckle length, with T{sub c} the laser coherence time. The BSBS spatial gain rate is approximately the sum of that due to CBSBS, and a part which is independent of diffraction and varies linearly with T{sub c}. The CBSBS spatial gain rate may be reduced significantly by the temporal bandwidth of KrF-based laser systems compared to the bandwidth currently available to temporally smoothed glass-based laser systems.

- Authors:

- Department of Mathematics and Statistics, University of New Mexico, Albuquerque, New Mexico 87131 (United States)
- (Russian Federation)
- Theoretical Division, Los Alamos National Laboratory, MS-B213, Los Alamos, New Mexico 87545 (United States)
- (United States)

- Publication Date:

- OSTI Identifier:
- 22407985

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Physics of Plasmas; Journal Volume: 22; Journal Issue: 1; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; BACKSCATTERING; DIFFRACTION; LASERS; PHOTON BEAMS; RANDOM PHASE APPROXIMATION; RANDOMNESS

### Citation Formats

```
Korotkevich, Alexander O., Lushnikov, Pavel M., E-mail: plushnik@math.unm.edu, Landau Institute for Theoretical Physics, 2 Kosygin Str., Moscow 119334, Rose, Harvey A., and New Mexico Consortium, Los Alamos, New Mexico 87544.
```*Beyond the random phase approximation: Stimulated Brillouin backscatter for finite laser coherence times*. United States: N. p., 2015.
Web. doi:10.1063/1.4906057.

```
Korotkevich, Alexander O., Lushnikov, Pavel M., E-mail: plushnik@math.unm.edu, Landau Institute for Theoretical Physics, 2 Kosygin Str., Moscow 119334, Rose, Harvey A., & New Mexico Consortium, Los Alamos, New Mexico 87544.
```*Beyond the random phase approximation: Stimulated Brillouin backscatter for finite laser coherence times*. United States. doi:10.1063/1.4906057.

```
Korotkevich, Alexander O., Lushnikov, Pavel M., E-mail: plushnik@math.unm.edu, Landau Institute for Theoretical Physics, 2 Kosygin Str., Moscow 119334, Rose, Harvey A., and New Mexico Consortium, Los Alamos, New Mexico 87544. Thu .
"Beyond the random phase approximation: Stimulated Brillouin backscatter for finite laser coherence times". United States.
doi:10.1063/1.4906057.
```

```
@article{osti_22407985,
```

title = {Beyond the random phase approximation: Stimulated Brillouin backscatter for finite laser coherence times},

author = {Korotkevich, Alexander O. and Lushnikov, Pavel M., E-mail: plushnik@math.unm.edu and Landau Institute for Theoretical Physics, 2 Kosygin Str., Moscow 119334 and Rose, Harvey A. and New Mexico Consortium, Los Alamos, New Mexico 87544},

abstractNote = {We developed a linear theory of backward stimulated Brillouin scatter (BSBS) of a spatially and temporally random laser beam relevant for laser fusion. Our analysis reveals a new collective regime of BSBS (CBSBS). Its intensity threshold is controlled by diffraction, once cT{sub c} exceeds a laser speckle length, with T{sub c} the laser coherence time. The BSBS spatial gain rate is approximately the sum of that due to CBSBS, and a part which is independent of diffraction and varies linearly with T{sub c}. The CBSBS spatial gain rate may be reduced significantly by the temporal bandwidth of KrF-based laser systems compared to the bandwidth currently available to temporally smoothed glass-based laser systems.},

doi = {10.1063/1.4906057},

journal = {Physics of Plasmas},

number = 1,

volume = 22,

place = {United States},

year = {Thu Jan 15 00:00:00 EST 2015},

month = {Thu Jan 15 00:00:00 EST 2015}

}

DOI: 10.1063/1.4906057

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