Observations of relativistic plasmas waves excited by a 1.064 µm and 1.053 µm laser beat

A. Dyson, A. Dangor, A. Dymoke-Bradshaw, T. Ashfar-Rad, P. Gibbon, A. Bell, C. Danson, Chris Edwards, G. Amiranoff, G. Matthieusent, Seppo Karttunen, Rainer Salomaa

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Abstract

We report observations of a relativistic plasma wave excited by two copropagating laser beams with frequency difference close to the plasma frequency in a fully ionized hydrogen plasma. The laser beams were at 1.064 µm (Nd:YAG) and 1.053 µm (Nd:YLF) of 200 ps duration and focused to a ≈ 7× diffraction limit spot with peak irradiance of 2×1014 W cm−2. The plasma wave was detected by monitoring the forward-scattered spectrum of a third copropagating laser beam at 0.526 µm. A novel use of Moire deflectrometry ensured the pump beams and probe beam were copropagating at focus. The inferred plasma wave density modulation δn/n is about 1–2% and corresponds to a longitudinal electric field of about 109 V m−1. The plasma wave was observed to exist for a time τp ≤ 50 ps. These results are not in agreement with theoretical predictions for relativistic detuning which give δn/n ≈ 8%, τp ≈ 200 ps and suggest that there is some mechanism limiting the growth of the plasma wave. Simulations indicate that this is due to either ponderomotive blowoff taking the plasma off resonant density or to the modulational instability.
Original languageEnglish
Pages (from-to)505-525
Number of pages21
JournalPlasma Physics and Controlled Fusion
Volume38
Issue number4
DOIs
Publication statusPublished - 1996
MoE publication typeA1 Journal article-refereed

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Plasma waves
relativistic plasmas
plasma waves
synchronism
Lasers
Laser beams
lasers
laser beams
Plasmas
flameout
Plasma stability
hydrogen plasma
plasma frequencies
irradiance
yttrium-aluminum garnet
Diffraction
Electric fields
Modulation
Pumps
pumps

Cite this

Dyson, A., Dangor, A., Dymoke-Bradshaw, A., Ashfar-Rad, T., Gibbon, P., Bell, A., ... Salomaa, R. (1996). Observations of relativistic plasmas waves excited by a 1.064 µm and 1.053 µm laser beat. Plasma Physics and Controlled Fusion, 38(4), 505-525. https://doi.org/10.1088/0741-3335/38/4/005
Dyson, A. ; Dangor, A. ; Dymoke-Bradshaw, A. ; Ashfar-Rad, T. ; Gibbon, P. ; Bell, A. ; Danson, C. ; Edwards, Chris ; Amiranoff, G. ; Matthieusent, G. ; Karttunen, Seppo ; Salomaa, Rainer. / Observations of relativistic plasmas waves excited by a 1.064 µm and 1.053 µm laser beat. In: Plasma Physics and Controlled Fusion. 1996 ; Vol. 38, No. 4. pp. 505-525.
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title = "Observations of relativistic plasmas waves excited by a 1.064 µm and 1.053 µm laser beat",
abstract = "We report observations of a relativistic plasma wave excited by two copropagating laser beams with frequency difference close to the plasma frequency in a fully ionized hydrogen plasma. The laser beams were at 1.064 µm (Nd:YAG) and 1.053 µm (Nd:YLF) of 200 ps duration and focused to a ≈ 7× diffraction limit spot with peak irradiance of 2×1014 W cm−2. The plasma wave was detected by monitoring the forward-scattered spectrum of a third copropagating laser beam at 0.526 µm. A novel use of Moire deflectrometry ensured the pump beams and probe beam were copropagating at focus. The inferred plasma wave density modulation δn/n is about 1–2{\%} and corresponds to a longitudinal electric field of about 109 V m−1. The plasma wave was observed to exist for a time τp ≤ 50 ps. These results are not in agreement with theoretical predictions for relativistic detuning which give δn/n ≈ 8{\%}, τp ≈ 200 ps and suggest that there is some mechanism limiting the growth of the plasma wave. Simulations indicate that this is due to either ponderomotive blowoff taking the plasma off resonant density or to the modulational instability.",
author = "A. Dyson and A. Dangor and A. Dymoke-Bradshaw and T. Ashfar-Rad and P. Gibbon and A. Bell and C. Danson and Chris Edwards and G. Amiranoff and G. Matthieusent and Seppo Karttunen and Rainer Salomaa",
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Dyson, A, Dangor, A, Dymoke-Bradshaw, A, Ashfar-Rad, T, Gibbon, P, Bell, A, Danson, C, Edwards, C, Amiranoff, G, Matthieusent, G, Karttunen, S & Salomaa, R 1996, 'Observations of relativistic plasmas waves excited by a 1.064 µm and 1.053 µm laser beat', Plasma Physics and Controlled Fusion, vol. 38, no. 4, pp. 505-525. https://doi.org/10.1088/0741-3335/38/4/005

Observations of relativistic plasmas waves excited by a 1.064 µm and 1.053 µm laser beat. / Dyson, A.; Dangor, A.; Dymoke-Bradshaw, A.; Ashfar-Rad, T.; Gibbon, P.; Bell, A.; Danson, C.; Edwards, Chris; Amiranoff, G.; Matthieusent, G.; Karttunen, Seppo; Salomaa, Rainer.

In: Plasma Physics and Controlled Fusion, Vol. 38, No. 4, 1996, p. 505-525.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Observations of relativistic plasmas waves excited by a 1.064 µm and 1.053 µm laser beat

AU - Dyson, A.

AU - Dangor, A.

AU - Dymoke-Bradshaw, A.

AU - Ashfar-Rad, T.

AU - Gibbon, P.

AU - Bell, A.

AU - Danson, C.

AU - Edwards, Chris

AU - Amiranoff, G.

AU - Matthieusent, G.

AU - Karttunen, Seppo

AU - Salomaa, Rainer

N1 - Project code: ENE9606

PY - 1996

Y1 - 1996

N2 - We report observations of a relativistic plasma wave excited by two copropagating laser beams with frequency difference close to the plasma frequency in a fully ionized hydrogen plasma. The laser beams were at 1.064 µm (Nd:YAG) and 1.053 µm (Nd:YLF) of 200 ps duration and focused to a ≈ 7× diffraction limit spot with peak irradiance of 2×1014 W cm−2. The plasma wave was detected by monitoring the forward-scattered spectrum of a third copropagating laser beam at 0.526 µm. A novel use of Moire deflectrometry ensured the pump beams and probe beam were copropagating at focus. The inferred plasma wave density modulation δn/n is about 1–2% and corresponds to a longitudinal electric field of about 109 V m−1. The plasma wave was observed to exist for a time τp ≤ 50 ps. These results are not in agreement with theoretical predictions for relativistic detuning which give δn/n ≈ 8%, τp ≈ 200 ps and suggest that there is some mechanism limiting the growth of the plasma wave. Simulations indicate that this is due to either ponderomotive blowoff taking the plasma off resonant density or to the modulational instability.

AB - We report observations of a relativistic plasma wave excited by two copropagating laser beams with frequency difference close to the plasma frequency in a fully ionized hydrogen plasma. The laser beams were at 1.064 µm (Nd:YAG) and 1.053 µm (Nd:YLF) of 200 ps duration and focused to a ≈ 7× diffraction limit spot with peak irradiance of 2×1014 W cm−2. The plasma wave was detected by monitoring the forward-scattered spectrum of a third copropagating laser beam at 0.526 µm. A novel use of Moire deflectrometry ensured the pump beams and probe beam were copropagating at focus. The inferred plasma wave density modulation δn/n is about 1–2% and corresponds to a longitudinal electric field of about 109 V m−1. The plasma wave was observed to exist for a time τp ≤ 50 ps. These results are not in agreement with theoretical predictions for relativistic detuning which give δn/n ≈ 8%, τp ≈ 200 ps and suggest that there is some mechanism limiting the growth of the plasma wave. Simulations indicate that this is due to either ponderomotive blowoff taking the plasma off resonant density or to the modulational instability.

U2 - 10.1088/0741-3335/38/4/005

DO - 10.1088/0741-3335/38/4/005

M3 - Article

VL - 38

SP - 505

EP - 525

JO - Plasma Physics and Controlled Fusion

JF - Plasma Physics and Controlled Fusion

SN - 0741-3335

IS - 4

ER -