Soft X-ray scattering using FEL radiation for probing near-solid density plasmas at few electron volt temperatures

Toleikis, S.; Fäustlin, R. R.; Cao, Leifeng; Döppner, T.; Düsterer, S.; Förster, E.; Fortmann, C.; Glenzer, S. H.; Göde, S.; Gregori, G.; Irsig, Robert; Laarmann, Tim; Lee, H.J.; Li, B.; Mithen, J.; Meiwes‐Broer, Karl‐Heinz; Przystawik, Andreas; Radcliffe, P.; Redmer, R.; Tavella, F.; Thiele, R.; Tiggesbäumker, J.; Trường, Nguyễn Xuân; Uschmann, I.; Zastrau, U.; Tschentscher, Th.

doi:10.1016/j.hedp.2009.06.012

Cited by 23 publications

(22 citation statements)

References 24 publications

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“…Figure 1 shows a schematic of the experiment. The FEL pulses hit the liquid hydrogen jet which has a diameter of 20 m, an atomic density of 4:2 Â 10 22 cm À3 , and a temperature of 2 meV, prepared in a liquid helium cooled cryostat [19]. With 60 ms À1 flow velocity of the hydrogen jet each pulse scatters from an unperturbed region of the sample.…”

mentioning

confidence: 99%

Observation of Ultrafast Nonequilibrium Collective Dynamics in Warm Dense Hydrogen

Fäustlin¹,

Bornath²,

Döppner³

et al. 2010

Phys. Rev. Lett.

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103

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We investigate ultrafast (fs) electron dynamics in a liquid hydrogen sample, isochorically and volumetrically heated to a moderately coupled plasma state. Thomson scattering measurements using 91.8 eV photons from the free-electron laser in Hamburg (FLASH at DESY) show that the hydrogen plasma has been driven to a nonthermal state with an electron temperature of 13 eV and an ion temperature below 0.1 eV, while the free-electron density is 2:8 Â 10 20 cm À3 . For dense plasmas, our experimental data strongly support a nonequilibrium kinetics model that uses impact ionization cross sections based on classical free-electron collisions. The investigation of warm dense matter (WDM) is one of the grand challenges of contemporary physics [1]. WDM is a plasma state characterized by moderate-tostrong interparticle coupling which takes place at freeelectron temperatures of several eV and free-electron densities around solid density [1]. It is present in many physical environments, such as planetary interiors [2,3], gravitationally collapsing protostellar disks, laser matter interaction and particularly during the implosion of an inertial confinement fusion capsule [4]. While in the astrophysical context WDM exists under stable conditions, in the laboratory it is achieved only as a transient state bridging condensed matter and hot plasma regimes. Here, we report on the first investigation of the nonequilibrium transition of hydrogen from a liquid to a moderately coupled plasma on the fs time scale, induced by highly intense soft-x-ray irradiation. This is an important step towards the investigation of strongly-coupled plasmas which are within reach of current light sources such as the Linac Coherent Light Source (LCLS). Our measurement enables unprecedented direct tests of nonequilibrium statistical models beyond mean field theories in a regime where collision and relaxation processes are dominant [5][6][7].The use of x-ray scattering for the investigation of dense, strongly-coupled plasmas was successfully demonstrated in the past decade [5,[7][8][9][10][11]. This technique is the x-ray analog of optical Thomson scattering (TS) [12] and enables the experimental determination of plasma parameters in dense systems where optical light cannot penetrate. While previous experiments were carried out using highenergy laser facilities, the advent of soft-and hard-x-ray free-electron lasers (FELs) makes ultrashort high brightness beams available for this type of research [13,14]. This Letter reports on ultrafast heating of liquid hydrogen and TS measurement of dense plasma parameters using softx-ray FEL radiation. For the first time, nonequilibrium distributions are observed and the underlying relaxation dynamics are compared with kinetic models showing electron relaxation times in the order of 20 fs, thus, shorter than the pulse duration.The scattering taking place is collective TS, which is characterized by a spectrally blue and red shifted response due to collective electron motion, plasmons, and nearly elastic scattering due t...

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mentioning

confidence: 99%

Observation of Ultrafast Nonequilibrium Collective Dynamics in Warm Dense Hydrogen

Fäustlin¹,

Bornath²,

Döppner³

et al. 2010

Phys. Rev. Lett.

Self Cite

103

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“…7.49) [42,64,66,77,126,137,152,173,174,179,210,236,238,248]. This will enable, in particular, studies of three-dimensional biological structures as well as determination of the location and role of its specific constituent structural elements, which is of great importance in developing new-generation medicines and polymers, as well as in constructing complex spatial molecular structures.…”

Section: Laser-plasma Acceleration Of Charged Particlesmentioning

confidence: 99%

Technical Applications of the Physics of High Energy Densities

Фортов¹

2016

Extreme States of Matter

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“…As sketched in Fig. 6, the plasma will be generated by the Titanium:Sapphire pump-probe laser system available at the FLASH I experimental hall [44] with laser parameters comparable to the parameters used for the calculations in Sec. 4.…”

Section: Proposed Experimental Setupmentioning

confidence: 99%

X-ray Thomson scattering diagnostics of impact ionization in laser-driven carbon foils

Sperling¹,

Zastrau²,

Toleikis³

et al. 2015

J. Phys. B: At. Mol. Opt. Phys.

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Abstract.We have studied the light-matter interaction of ultra-short, intense optical laser fields with thin carbon foils via particle-in-cell simulations. Especially, the influence of additional impact ionization on the density and temperature of the generated plasma and on the corresponding Thomson scattering spectra was investigated which has been found essential for laser intensities I > 10 16 W/cm 2 . We predict a pump-probe experiment at the free electron laser FLASH in order to verify the importance of this effect in the laser-matter interaction on ultra-short time scales and to check our predictions quantitatively.X-ray Thomson scattering diagnostics of impact ionization in laser-driven carbon foils2

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Soft X-ray scattering using FEL radiation for probing near-solid density plasmas at few electron volt temperatures

Cited by 23 publications

References 24 publications

Observation of Ultrafast Nonequilibrium Collective Dynamics in Warm Dense Hydrogen

Observation of Ultrafast Nonequilibrium Collective Dynamics in Warm Dense Hydrogen

Technical Applications of the Physics of High Energy Densities

X-ray Thomson scattering diagnostics of impact ionization in laser-driven carbon foils

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