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LPA Online Seminars

[JuSPARC Seminar] Plasma mirrors as a realistic path towards the Schwinger limit

durch Dr. Henri Vinventi (CEA)

Europe/Berlin
Beschreibung

I present the strategies that we are developing at CEA to very soon reach unexplored regimes of strong-field Quantum Electrodynamics (SF-QED) with currently available high-power Petawatt (PW) lasers. Such regimes occur at extreme light intensities, the most famous example being the optical breakdown of the quantum vacuum occurring beyond light intensities of 10^29W/cm^2 (the so-called Schwinger limit). This limit is more than 7 orders of magnitude higher than the present record in laser intensity (5x10^22W/cm^2) set by a 4PW laser. It is thus impossible to reach with conventional optical laser technology and new paradigms are absolutely necessary to close this gap.

In this context, our approach consists in directly boosting the intensity of a PW laser pulse upon reflection off a curved relativistic plasma mirror. A relativistic plasma mirror can be formed by the PW laser pulse itself after focusing on an initially solid target. 

In my talk, I first discuss how to efficiently curve the surface of a plasma mirror in experiments using an all-optical method that simply relies on the incident laser radiation pressure.

Then, I detail our recent theoretical and numerical work showing that with a 2 PW incident laser pulse, intensities above 10^25W/cm2 could already be reached at the focus of a plasma mirror curved by laser radiation pressure. Even though these intensities are below the Schwinger limit, we show that they can already allow for very clear signatures of SF-QED processes when a secondary target is placed at the focus of the plasma mirror. In particular, prolific electron-positron pair production by the non-linear Breit-Wheeler process occurs in the secondary target and positrons are accelerated up to 4GeV with 0.16nC total positron charge. This is more than three orders of magnitude enhancement in terms of charge and energy as compared to what could be achieved by a single 10PW laser pulse (without intensity boosting with a curved relativistic mirror).

Finally, I discuss the limits of this scheme and our recent developments to realistically increase the radiation pressure curvature for approaching the Schwinger limit of 10^29W/cm2 around which the quantum vacuum would breakdown.  

Access code: 020654