Plasma production by irradiating freely falling deuterium pellets with a high-power laser

Baumhacker, H.; Brinkschulte, H.; Lang, R.; Riedmueller, W.; Salvat, M.

doi:10.1063/1.89441

Cited by 11 publications

(11 citation statements)

References 4 publications

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“…These lasers produced electron and ion kinetic energies of hundred to few kilo-electronvolts by thermally heating the plasma [e.g. [19][20][21][22]. Laser plasmas were then amongst others tensity.…”

Section: Laser Driven Sources Of Radiationmentioning

confidence: 99%

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Relativistically Intense Laser–Microplasma Interactions

Ostermayr

2019

Springer Theses

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Diese Arbeit behandelt verschiedene Aspekte der Interaktion von relativistisch intensiven Laserpulsen mit Mikroplasmen. Dafür wurde zunächst eine Paul-Falle entwickelt, welche vollständig isolierte und definierte Mikrokugeln als Ziel für Experimente mit fokussierten Peta-Watt Laser-Pulsen bereitstellt. Solche Interaktionen wurden dann in der Theorie, in numerischen Simulationen und in einer Serie von Experimenten untersucht. Die erste wichtige Beobachtung hierbei war die Erzeugung manipulierbarer Protonenstrahlen mit kinetischen Energienüber 10 MeV. Die Modifikation in den spektralen und räumlichen Verteilungen erfolgte durch die Variation des Beschleunigungsmechanismus. Dies beinhaltet das Auftreten von Protonenstrahlen mit begrenzter spektraler Bandbreite, welcheähnliche Lasergetriebene Quellen in kinetischer Energie und/oder Teilchenfluenzübertreffen. Die relative Bandbreite von 20-25% wird durch die (isotrope) Coulomb Explosion oder durch gerichtete Beschleunigungsprozesse erreicht (Abb. 1a, sec. 5.3 und 5.4). Im zweiten Teil der Ar-Abbildung 1 | Zentrale Ergebnisse. a. Ionenquellen mit limitierter spektraler Bandbreite in dieser Arbeit (rot) im Kontext früherer Experimente mit Laser-Ionen-Beschleunigern (Quellen: [1-10]). Markiert ist je das spektrale Maximum, Fehlerbalken markieren die spektrale Breite (volle Breite bei halbem Maximalwert). b. Beispiel eines bimodalen Röntgen-und Protonenbildes (übereinander registriert). Der Skalenbalken entspricht 1 cm. Intensitäten sind in relativen Skalen angegeben und das Protonenbild wird zu 40% transparent dargestellt. beit wurden Mikronadeln mit Peta-Watt Laser-Pulsen beschossen um Röntgen-und Protonenstrahlen mit jeweils nur einigen Mikrometern effektiver Quellgröße zu erzeugen. Im Röntgenspektrum wurde ein Maximum um 6 keV und messbares Signal bisüber 10 keV beobachtet. Das Protonenspektrum zeigte erneut die quasi-monoenergetische Verteilung mit Peak-Energienüber 10 MeV (Abb. 1a, sec. 6.1). Nach der Charakterisierung der Quelle wurde diese für Bildgebung genutzt. Dabei konnte insbesondere die gleichzeitige Aufnahme von Röntgen-und Protonenbildern mit einem einzelnen Laserschuß gezeigt werden (Abb. 1b). Die Besonderheiten der Quelle erlaubten zudem Röntgenaufnahmen mit starkem Phasen-Kontrast Anteil, sowie die Untersuchung von quantitativen Einzelschuß Protonen-Radiographien.

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Section: Laser Driven Sources Of Radiationmentioning

confidence: 99%

“…Already early after the invention of the laser, the use of isolated targets in lasermatter interaction has been suggested and tested [19][20][21][22]. The first motivation to use isolated targets in laser plasma experiments is therefore nothing different from 8 1.…”

Section: Laser Driven Sources Of Radiationmentioning

confidence: 99%

Relativistically Intense Laser–Microplasma Interactions

Ostermayr

2019

Springer Theses

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“…It was mentioned in Section 2 above that the pellet radius could increase substantially over a period of ~ 1 /is, thereby affecting the ablation rate. The explosive expansion of initially solid pellet material following (or during) laser irradiation has been observed in deuterium [2,3], polythene [15,18] and polystyrene [18]. The very high expansion velocities (up to 3 X 10 6 cms" 1 for deuterium [2]) leave only a limited time for ionization by ablation before the pellet becomes underdense.…”

Section: Disintegration Of Laser-shocked Pelletsmentioning

confidence: 99%

“…A number of current experiments involve the use of lasers to create plasmas as a means of filling magnetic fusion devices with hot plasma [1][2][3][4]. Potential advantages of this method of filling are the production of dense and hot plasmas, the avoidance of heating currents, and isolation of the plasma from the walls, reducing impurities.…”

Section: Introductionmentioning

confidence: 99%

Scaling laws for plasma production and pellet acceleration by laser

McGeoch¹

1979

Nucl. Fusion

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The results from a spherical-symmetry hydrodynamic calculation are adapted to describe the production of large plasmas by the laser ablation of solid-density pellets. Expressions are given for the rate of ablation, plasma temperature and ion energy. The upper limit on the ionized particle number is set by pellet disintegration following heating by laser-driven shock. Scaling laws are derived for the total plasma energy and particle number. Plasma conductivity transforms one-sided illumination into an approximately spherical ablation, allowing a discussion of the scaling laws for laser-induced acceleration. The reduction in laser acceleration due to quasi-spherical ablation has negative implications for laser acceleration as a method of reactor re-fuelling.

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“…Highly localized plasmas produced by intense laser pulses played an important role in the early development and understanding of laser plasma physics [1][2][3][4]. Meanwhile, the 10 GW giant laser pulses from the 1960s constitute the pedestal or prepulse of today's super-intense chirped pulse amplified Petawatt lasers.…”

Section: Introductionmentioning

confidence: 99%

Proton acceleration by irradiation of isolated spheres with an intense laser pulse

et al. 2016

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We report on experiments irradiating isolated plastic spheres with a peak laser intensity of 2-3×10^{20}Wcm^{-2}. With a laser focal spot size of 10 μm full width half maximum (FWHM) the sphere diameter was varied between 520 nm and 19.3 μm. Maximum proton energies of ∼25 MeV are achieved for targets matching the focal spot size of 10 μm in diameter or being slightly smaller. For smaller spheres the kinetic energy distributions of protons become nonmonotonic, indicating a change in the accelerating mechanism from ambipolar expansion towards a regime dominated by effects caused by Coulomb repulsion of ions. The energy conversion efficiency from laser energy to proton kinetic energy is optimized when the target diameter matches the laser focal spot size with efficiencies reaching the percent level. The change of proton acceleration efficiency with target size can be attributed to the reduced cross-sectional overlap of subfocus targets with the laser. Reported experimental observations are in line with 3D3V particle in cell simulations. They make use of well-defined targets and point out pathways for future applications and experiments.

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Plasma production by irradiating freely falling deuterium pellets with a high-power laser

Cited by 11 publications

References 4 publications

Relativistically Intense Laser–Microplasma Interactions

Relativistically Intense Laser–Microplasma Interactions

Scaling laws for plasma production and pellet acceleration by laser

Proton acceleration by irradiation of isolated spheres with an intense laser pulse

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