S. Kalmykov

United States Air Force Research Laboratory

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Co-Authors

Gennady Shvets

Cornell University

X. Davoine

CEA DAM Île-de-France

S. A. Yi

Jilin University

M. C. Downer

The University of Texas at Austin

S. Alexander Reed

Ithaca College

B. A. Shadwick

University of Nebraska–Lincoln

A. Maksimchuk

University of Michigan–Ann Arbor

Andreas Schmitt-Sody

Kirtland Air Force Base

S. S. Bulanov

Lawrence Berkeley National Laboratory

G. Kalintchenko

University of Michigan–Ann Arbor

Cooperative Institutions

The University of Texas at Austin

University of Michigan–Ann Arbor

University of Nebraska–Lincoln

Optical Sciences (United States)

Lawrence Livermore National Laboratory

Centre National de la Recherche Scientifique

École Polytechnique

Commissariat à l'Énergie Atomique et aux Énergies Alternatives

University of Maryland, College Park

Lawrence Berkeley National Laboratory

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Improved particle statistics for laser-plasma self-injection simulations

AIP conference proceedings (2012)

B. Cowan S. Kalmykov B. A. Shadwick K. J. Bunkers David Bruhwiler

We describe methods for improving the accuracy of injected particle beams by selectively enhancing the particle statistics in particle-in-cell simulations, using reduced model computations as a guide. We demonstrate convergence of key beam parameters in two dimensions, and show improved noise properties in three dimensions.

Particle (ecology)

Particle-in-cell

10.1063/1.4773725

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Citations (1)

Dark-current-free laser-plasma acceleration in blowout regime using nonlinear plasma lens

AIP conference proceedings (2012)

S. Kalmykov

It is demonstrated that a thin dense plasmas lab (lens), placed before a multi-centimeter-length, low-density plasma (accelerator), overfocuses an incident petawatt laser pulse at a controlled location inside the accelerator, creating an expanding electron density bubble that traps plasma electrons over a brief time interval. As soon as the pulse stabilizes and self-guiding begins, the bubble stabilizes and transforms into the first (non-broken) bucket of a conventional three-dimensional nonlinear plasma wave, eliminating any chance for further injection. A well collimated, quasi-monoenergetic electron bunch with a zero low-energy background further accelerates to a multi-GeV energy.

Collimated light

Plasma acceleration

Plasma window

10.1063/1.4788989

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Frequency Domain Tomography Of Evolving Laser-Plasma Accelerator Structures

AIP conference proceedings (2009)

Peng Dong S. Alexander Reed S. Kalmykov Gennady Shvets Mike Downer

Frequency Domain Holography (FDH), a technique for visualizing quasistatic objects propagating near the speed of light, has produced "snapshots" of laser wakefields, but they are averaged over structural variations that occur during propagation through the plasma medium. Here we explore via simulations a generalization of FDH—that we call Frequency Domain Tomography (FDT)—that can potentially record a time sequence of quasistatic snapshots, like the frames of a movie, of the wake structure as it propagates through the plasma. FDT utilizes a several probe‐reference pulse pairs that propagate obliquely to the drive pulse and wakefield, along with tomographic reconstruction algorithms similar to those used in medical CAT scans.

Quasistatic process

Tomographic reconstruction

10.1063/1.3080893

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Plasma beatwave accelerator based on a nonlinear bistability of relativistic plasma waves

Gennady Shvets Mikhail Tushentsov S. Kalmykov

Summary form only given. Plasma beatwave is one of the originally proposed schemes for making a plasma-based accelerator. Its traditional implementation assumes that the plasma wave is a linear oscillator driven by the ponderomotive force of the two lasers detuned by the plasma frequency. We demonstrate how the off-resonance excitation of the plasma wave and the relativistic dependence of the plasma frequency on its amplitude can be used to observe the nonlinear bistability of the plasma wave. The relativistic threshold for observing the nonlinear bistability is derived and confirmed using particle in cell simulations. One of the surprising results is the realization that a very long laser beatwave pulse slightly detuned from the nonrelativistic plasma wave resonance can excite plasma waves behind the pulse if the peak pulse amplitude exceeds the threshold. Specific examples of laser and plasma parameters relevant to high-gradient plasma accelerators given. Also, excitation of plasma wakes by a strongly modulated (for example, by an FEL interaction) electron beam is considered, and the possibility of developing a combined accelerator/fs-injector is discussed.

Ponderomotive force

Relativistic plasma

Bistability

10.1109/plasma.2004.1339697

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Ultrabroadband microwave radiation from near- and mid-infrared laser-produced plasmas in air

Physical review. A/Physical review, A (2021)

Alexander Englesbe Jennifer Elle R. Schwartz Travis Garrett Daniel Woodbury

An ultrashort laser pulse focused in air creates a plasma that radiates broadband electromagnetic waves. We experimentally compare the generation of microwaves from plasmas produced with two different laser systems that operate in the near- and mid-infrared regimes. Changing the laser wavelength increases the microwave power by 100 times and changing the input pulse energy allows for tuning of the microwave frequency spectrum, which we absolutely calibrate over a range of 2--70 GHz. The variation of the spectrum with laser pulse energy confirms the existence of a distinct mechanism that generates microwave radiation from laser-produced plasmas in gases. We propose that a radial diffusive expansion wave of the plasma electrons drives a longitudinal current along the plasma surface whose amplitude varies with the total residual electron energy imparted by the laser field and this longitudinal current produces the detected radiation.

Electromagnetic spectrum

Pulse duration

10.1103/physreva.104.013107

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Citations (13)

Laser wakefield acceleration by petawatt ultra-short laser pulses

APS (2004)

L. M. Gorbunov S. Kalmykov P. Mora

Chirped pulse amplification

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Preparation For Laser Wakefield Experiments Driven by the Texas Petawatt Laser System

AIP conference proceedings (2009)

S. Alexander Reed S. Kalmykov E. Gaul M. Martinez W. Henderson

Laboratories around the world are planning petawatt laser driven experiments. The Texas petawatt laser offers the ability to demonstrate laser wake field acceleration (LWFA) in a unique regime with pulse duration (∼160 fs) shorter than other petawatt scale systems currently in operation or under development. By focusing the 1.25 PW, 200 J, 160 fs pulses to peak intensity ∼1019 W/cm2, multi‐GeV electron bunches can be produced from a low density He gas jet. The rarefied plasma density (5×1016−1017 cm−3) required for near‐resonant LWFA minimizes plasma lensing and offers long dephasing length for electron acceleration over distances (∼10 cm) exceeding the Rayleigh range. Because of the high power, the laser can be focused to a spot (r0∼100 microns) greater than the plasma wavelength (r0>λp), thus minimizing radial propagation effects. Together these properties enable the laser pulse to self‐guide without the use of a preformed channel lending simplicity and stability to the overall acceleration process. Particle‐in‐cell (PIC) simulations show the laser experiences self‐focusing which, because of ultrashort pulse duration, does not lead to a collapse of the wakefield and can generate over 3 GeV electron energy. The presented material will include details of initial measurements of the Texas petawatt laser system, simulations of laser wakefield acceleration for the given laser parameters and the experimental setup currently under construction.

Chirped pulse amplification

Pulse duration

Plasma acceleration

Dephasing

Rayleigh length

10.1063/1.3080901

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Surface wave accelerator based on silicon carbide: theoretical study

AIP conference proceedings (2009)

S. Kalmykov Dmitriy Korobkin Burton Neuner Gennady Shvets C. B. Schroeder

Compact near‐field solid‐state accelerating structure powered by a carbon dioxide (CO2) laser is considered. The accelerating luminous transverse magnetic mode is excited in a few‐micron wide evacuated planar channel between two silicon carbide (SiC) films grown on silicon (Si) wafers. Laser coupling to this mode is accomplished through the properly designed Si gratings. Operating wavelength is dictated by the frequency‐dependent dielectric permittivity of SiC and the channel width. The geometric loss factor κ of the accelerating mode is computed. It is found that the unwanted excitation of the guided modes in Si wafers reduces the laser coupling efficiency and increases the fields inside the Si wafer.

Transverse mode

10.1063/1.3080964

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Citations (1)

Petawatt-laser-driven wakefield acceleration of electrons to 2 GeV in 1017 cm−3 plasma

AIP conference proceedings (2012)

Xiao-Yong Wang Rafal Zgadzaj N. Fazel S. A. Yi X. Zhang

Electron self-injection into a laser-plasma accelerator (LPA) driven by the Texas Petawatt (TPW) laser is reported at plasma densities 1.7 - 6.2 × 1017 cm−3. Energy and charge of the electron beam, ranging from 0.5 GeV to 2 GeV and tens to hundreds of pC, respectively, depended strongly on laser beam quality and plasma density. Angular beam divergence was consistently around 0.5 mrad (FWHM), while shot-to-shot pointing fluctuations were limited to ±1.4 mrad rms. Betatron x-rays with tens of keV photon energy are also clearly observed.

Betatron

Plasma acceleration

10.1063/1.4773719

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Citations (10)

Electron self-injection and trapping into an evolving plasma bubble

Bulletin of the American Physical Society (2009)

S. Kalmykov S. A. Yi Vladimir Khudik Gennady Shvets

The blowout (or bubble) regime of laser wakefield acceleration is promising for generating monochromatic high-energy electron beams out of low-density plasmas. It is shown analytically and by particle-in-cell simulations that self-injection of the background plasma electrons into the quasistatic plasma bubble can be caused by slow temporal expansion of the bubble. Sufficient criteria for the electron trapping and bubble's expansion rate are derived using a semianalytic nonstationary Hamiltonian theory. It is further shown that the combination of bubble's expansion and contraction results in monoenergetic electron beams.

Monochromatic color

Quasistatic process

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