Wakefield-Induced Ionization injection in beam-driven plasma accelerators

We present a detailed analysis of the features and capabilities of Wakefield-Induced Ionization (WII) injection in the blowout regime of beam driven plasma accelerators. This mechanism exploits the electric wakefields to ionize electrons from a dopant gas and trap them in a well-defined region of the accelerating and focusing wake phase, leading to the formation of high-quality witness-bunches [Martinez de la Ossa et al., Phys. Rev. Lett. 111, 245003 (2013)]. The electron-beam drivers must feature high-peak currents ($I_b^0\gtrsim 8.5~\mathrm{kA}$) and a duration comparable to the plasma wavelength to excite plasma waves in the blowout regime and enable WII injection. In this regime, the disparity of the magnitude of the electric field in the driver region and the electric field in the rear of the ion cavity allows for the selective ionization and subsequent trapping from a narrow phase interval. The witness bunches generated in this manner feature a short duration and small values of the normalized transverse emittance ($k_p\sigma_z \sim k_p\epsilon_n \sim 0.1$). In addition, we show that the amount of injected charge can be adjusted by tuning the concentration of the dopant gas species, which allows for controlled beam loading and leads to a reduction of the total energy spread of the witness beams. Electron bunches, produced in this way, fulfil the requirements to drive blowout regime plasma wakes at a higher density and to trigger WII injection in a second stage. This suggests a promising new concept of self-similar staging of WII injection in steps with increasing plasma density, giving rise to the potential of producing electron beams with unprecedented energy and brilliance from plasma-wakefield accelerators

Chirp mitigation of plasma-accelerated beams using a modulated plasma density

Plasma-based accelerators offer the possibility to drive future compact light sources and high-energy physics applications. Achieving good beam quality, especially a small beam energy spread, is still one of the major challenges. For stable transport, the beam is located in the focusing region of the wakefield which covers only the slope of the accelerating field. This, however, imprints a longitudinal energy correlation (chirp) along the bunch. Here, we propose an alternating focusing scheme in the plasma to mitigate the development of this chirp and thus maintain a small energy spread

Correction to: The first-in-class alkylating deacetylase inhibitor molecule tinostamustine shows antitumor effects and is synergistic with radiotherapy in preclinical models of glioblastoma

The original article contained an error whereby Fig. 4 displayed incorrect magnification scales. This has now been corrected, and can be seen ahead and in the original article

Reinstated p53 response and high anti-T-cell leukemia activity by the novel alkylating deacetylase inhibitor tinostamustine

Non peer reviewe

The FLASHForward Facility at DESY

The FLASHForward project at DESY is a pioneering plasma-wakefield acceleration experiment that aims to produce, in a few centimetres of ionised hydrogen, beams with energy of order GeV that are of quality sufficient to be used in a free-electron laser. The plasma wave will be driven by high-current density electron beams from the FLASH linear accelerator and will explore both external and internal witness-beam injection techniques. The plasma is created by ionising a gas in a gas cell with a multi-TW laser system, which can also be used to provide optical diagnostics of the plasma and electron beams due to the <30 fs synchronisation between the laser and the driving electron beam. The operation parameters of the experiment are discussed, as well as the scientific program.Comment: 19 pages, 9 figure

Investigating the potentially contradictory microfoundations of financialization

The existing academic literature on financialization points to multiple instances in which firms attempt to demonstrate the vitality of their stock-market position in ways which ultimately prove to be self-harming. I demonstrate, in the first instance as a matt er of immanent logic, that these actions are linked to the interplay of contradictory tendencies in the microfoundations of financialization. Under conditions of financialization, firms create additional sources of credit to capitalize their productive activities by driving their stock price into greater increases than the market average, thereby generating capital gains. Yet, the more it becomes public knowledge that the financing tricks used to inflate the stock price provide no productive benefit to the firm, the more it would seem to create incentives for fund managers to hold portfolios that replicate the stock market as a whole. In this way, they will minimize their exposure to financial misrepresentation. Such a stance undermines financialized business models, but it does in any case conform to fund managers' basic theoretical training, which revolves around the logical demonstration that an individual stock cannot systematically out-perform the market average. I review the available empirical studies of fund manager decision-making to show that they find against the existence of a simple performativity loop operating between finance theory and fund manager behaviour. However, on many points the empirical evidence does confirm the theoretically derived conclusion concerning the potentially contradictory microfoundations of financialization. Fund managers often do act in a way which is consistent with finance theory's core claim that an index-tracking strategy represents the only equilibrium portfolio, even if this is only rarely as a result of the direct performativity of the theory

Shadow money and the public money supply: the impact of the 2007-2009 financial crisis on the monetary system

This article explores the effects of the political reactions to the 2007–2009 financial crisis on the monetary system. It chimes in with the view that shadow banks create ‘shadow money’, i.e. private substitutes for bank deposits. The article analyses how the three main forms of shadow money – money market fund shares, overnight repurchase agreements and asset-backed commercial papers – were affected by the short-term government intervention and medium-term regulation during and after the 2007–2009 financial crisis in the United States. The analysis reveals that the measures taken between 2007 and 2014 integrated some shadow money forms in the public money supply. In the year after the Lehman collapse, the initially private shadow money supply was either publicly backstopped or de-monetised as it had broken par to bank deposits. The public backstops took on the form of emergency facilities established by the Federal Reserve and guarantees proclaimed by the Treasury. Those backstops imply that the public institutional framework to protect bank deposits was extended to some forms of shadow money during the crisis. This tendency has continued in post-crisis regulation. Accordingly, the 2007–2009 financial crisis has triggered a paradigmatic change in the monetary system, attributable to the political decisions of US authorities