Particle-in-cell simulation of x-ray wakefield acceleration and betatron radiation in nanotubes

Abstract

Though wakefield acceleration in crystal channels has been previously proposed, x-ray wakefield acceleration has only recently become a realistic possibility since the invention of the single-cycled optical laser compression technique. We investigate the acceleration due to a wakefield induced by a coherent, ultrashort x-ray pulse guided by a nanoscale channel inside a solid material. By two-dimensional particlein-cell computer simulations, we show that an acceleration gradient of TeV=cm is attainable. This is about 3 orders of magnitude stronger than that of the conventional plasma-based wakefield accelerations, which implies the possibility of an extremely compact scheme to attain ultrahigh energies. In addition to particle acceleration, this scheme can also induce the emission of high energy photons at ∼Oð10-100Þ MeV. Our simulations confirm such high energy photon emissions, which is in contrast with that induced by the optical laser driven wakefield scheme. In addition to this, the significantly improved emittance of the energetic electrons has been discussed.

Wakefield acceleration

“…Because of this promise there have occurred many high field science labs in the world, to list several example of which: APRC (Advanced Photon Research Center and Kansai Photon Research Institute) of JAERI (Takuma 1996), APRI (Advanced Photon Fig. 30 Wakefields by a few-cycled 1 keV X-ray pulse (a 0 ~ O(1)), causing 10 TeV/m electric fields in the holed nanostructure (above) more strongly confined in the tube compared with the uniform solid case below (Zhang and Tajima 2016) Research Institute (Korea), ELI (Extreme Light Infrastructure) (three campuses of ELI-ALPS, ELI-Beams, ELI-NP) , XLS (Extreme Light Station at SIOM) (Tajima and Li 2018). These research activities no doubt further stimulate this already very exciting field further forward in the future.…”

“…The scaling of LWFA dictates that with high energy X-ray photons the critical density n cr increases by many orders of magnitude, allowing us to take even solid density electrons as an accelerating media (nanostructured materials, for example) (Tajima 2014;Shin 2014;Zhang and Tajima 2016). The adoption of nanostructured materials is a creative integration of (1) high density (solid density) media for LWFA and (2) an evacuated hole for accelerated particle that also focuses wakefields (Zhang and Tajima 2016). An exploratory research shows a remarkable clean wakefields excited at this solid density medium at the intensity of TeV/cm, opening up a "TeV on a chip" possibility.…”

Ultimate colliders for particle physics: Limits and possibilities

“…The latter leads to particles escaping from the driving field; thus, it was suggested that particles(muons) have to be accelerated in solids along major crystallographic directions, which provide a channeling effect in combination with low emittance determined by an Angstrom-scale aperture of the atomic tubes 10,11 . Channeling in the nanotubes was later brought up as a promising option [12][13][14] . Positively charged particles are channeled more robustly, as they are repelled from ions and thus experience weaker scattering.…”

“…Historically first was the suggestion to use ultrashort and powerful 40 keV X-ray pulses injected in the crystal at a proper angle to achieve Bormann anamalous transmission over longer distances 9 . Extreme X-ray pulse power density O(10 23−24 W/cm 2 ) can now be achieved at the SASE FELs like LCLS at SLAC, and the gradients of about 0.2[TV/m]•a 2 0 are predicated in CNTs which can lead to 100s of MeV of acceleration in few micron long structures 13,14 (here a 0 ∼ O(1) is the normalized field intensity of a O(1nm) wavelength laser). Further opportunities to increase the laser intensities can be offered by recently proposed ICAN and thin film compression schemes.…”

Creating localized plasma waves by ionization of doped semiconductors

“…These unique advantages combined with ionization enable dielectric laser acceleration of electrons [9][10][11], protons, and heavy ions [10][11][12]. Solid-state density plasma also offers an electrostatic potential in crystal channels to confine positively charged particles and accelerate them to energy near 300 GeV [13][14][15][16].…”