# Multi-GeV Laser Wakefield Electron Acceleration with PW Lasers
###### Abstract  
Laser wakefield electron acceleration (LWFA) is an emerging technology for the next generation of electron accelerators. As intense laser technology has rapidly developed, LWFA has overcome its limitations and has proven its possibilities to facilitate compact high-energy electron beams. Since high-power lasers reach peak power beyond petawatts (PW), LWFA has a new chance to explore the multi-GeV energy regime. In this article, we review the recent development of multi-GeV electron acceleration with PW lasers and discuss the limitations and perspectives of the LWFA with high-power lasers.  
petawatt laser; laser plasma; laser wakefield acceleration; compact electron accelerator; GeV electron beam +
Footnote †: journal: Applied Physics Letters  
_Review_  
Multi-GeV Laser Wakefield Electron Acceleration with PW Lasers  
[1 spontaneously happens in the plasma, which is called self-injection. Therefore, the whole acceleration process is highly nonlinear and unstable, limiting the electron energy [11; 12], beam quality and stability [13; 14]. Many studies are ongoing to solve these problems to improve the performance of LWFA.  
The advancement of high-power laser technology is essential for the enhancement of LWFA performance. Enormous efforts have been exerted to increase the laser's peak power and they consequently succeeded in building petawatt (PW) lasers [15]. The development of PW lasers provided a chance to explore a new regime of laser particle accelerations and relativistic laser-plasma interactions. In the last decade, several types of PW lasers have been used in LWFA experiments. A PW laser was demonstrated in Texas university, Austin, by adapting the CPA to an Nd:Glass laser [16]. This hybrid laser had a very low repetition rate, below one shot/hour. The most successful demonstration of PW lasers was based on Ti:Sapphire CPA lasers. These lasers can provide laser energy over 30 J, pulse duration of about 30 fs, and a repetition rate of over 0.1 shot/second [17]. Ti:Sapphire lasers with peak power over PW have been commercialized and installed in several research institutes for relativistic laser-plasma science. As the laser power increases, the achievable electron energy by LWFA has increased by more than an order of magnitude, compared to the first demonstration of the bubble-regime LWFA in 2004. Recently, multi-GeV electron beams were obtained with a centimeter-long medium [11; 18; 19]; the conventional radio-frequency (RF) acceleration technology requires a few hundred meters for such beams. In addition, many applications of LWFA or radiation sources from LWFA have been demonstrated in the last decade. Therefore, LWFA has the potential for compact linear accelerators and x-ray sources as the next generation of electron accelerators.  
In this paper, we review several exemplary experiments on LWFA with PW lasers. The large-scale laser facilities are installing or recently installed multi-PW lasers, e.g., the three pillars of extreme light infrastructures (ELI) [20], the Zetawatt-Equivalent Ultrashort Pulse Laser System (ZEUS) [21], the Exawatt Center for Extreme Light Studies (XCELS) [22], the Shanghai Superintense Ultrafast Laser Facility (SULF) [23], the Apollon laser [24], and the Center for Relativistic Laser Science (CoReLS) [25]. Thus, this review on the prominent experimental results on LWFA with PW lasers can be a valuable guide for the LWFA with the emerging high-power lasers.  
This article is organized into five sections, as follows. We explain the fundamental physics of the LWFA process briefly in Section 2 and address the representative experimental results on multi-GeV LWFA with PW lasers in Section 3. We discuss the perspective of LWFA with PW lasers in Section 4, then we conclude.