A comparison of g(1)(τ), g(3/2)(τ), and g(2)(τ), for radiation from harmonic oscillators in Brownian motion with coherent background
Authors:
Antonin Siciak,
Luis A. Orozco,
Mathilde Fouché,
William Guerin,
Robin Kaiser
Abstract:
We compare the field-field g(1)(τ), intensity-field g(3/2)(τ), and intensity-intensity g(2)(τ) correlation functions for models that are of relevance in astrophysics. We obtain expressions for the general case of a chaotic radiation, where the amplitude is Rician based on a model with an ensemble of harmonic oscillators in Brownian motion. We obtain the signal to noise ratios for two methods of me…
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We compare the field-field g(1)(τ), intensity-field g(3/2)(τ), and intensity-intensity g(2)(τ) correlation functions for models that are of relevance in astrophysics. We obtain expressions for the general case of a chaotic radiation, where the amplitude is Rician based on a model with an ensemble of harmonic oscillators in Brownian motion. We obtain the signal to noise ratios for two methods of measurement. The intensity-field correlation function signal to noise ratio scales with the first power of |g(1)(τ)|. This is in contrast with the well-established result of g(2)(τ) which goes as the square of |g(1)(τ)|.
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Submitted 13 July, 2020;
originally announced July 2020.
Probing Ultrafast Magnetic-Field Generation by Current Filamentation Instability in Femtosecond Relativistic Laser-Matter Interactions
Authors:
G. Raj,
O. Kononenko,
A. Doche,
X. Davoine,
C. Caizergues,
Y. -Y. Chang,
J. P. Couperus Cabadag,
A. Debus,
H. Ding,
M. Förster,
M. F. Gilljohann,
J. -P. Goddet,
T. Heinemann,
T. Kluge,
T. Kurz,
R. Pausch,
P. Rousseau,
P. San Miguel Claveria,
S. Schöbel,
A. Siciak,
K. Steiniger,
A. Tafzi,
S. Yu,
B. Hidding,
A. Martinez de la Ossa
, et al. (6 additional authors not shown)
Abstract:
We present experimental measurements of the femtosecond time-scale generation of strong magnetic-field fluctuations during the interaction of ultrashort, moderately relativistic laser pulses with solid targets. These fields were probed using low-emittance, highly relativistic electron bunches from a laser wakefield accelerator, and a line-integrated $B$-field of $2.70 \pm 0.39\,\rm kT\,μm$ was mea…
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We present experimental measurements of the femtosecond time-scale generation of strong magnetic-field fluctuations during the interaction of ultrashort, moderately relativistic laser pulses with solid targets. These fields were probed using low-emittance, highly relativistic electron bunches from a laser wakefield accelerator, and a line-integrated $B$-field of $2.70 \pm 0.39\,\rm kT\,μm$ was measured. Three-dimensional, fully relativistic particle-in-cell simulations indicate that such fluctuations originate from a Weibel-type current filamentation instability developing at submicron scales around the irradiated target surface, and that they grow to amplitudes strong enough to broaden the angular distribution of the probe electron bunch a few tens of femtoseconds after the laser pulse maximum. Our results highlight the potential of wakefield-accelerated electron beams for ultrafast probing of relativistic laser-driven phenomena.
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Submitted 28 July, 2019;
originally announced July 2019.