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A long, narrow, relativistic charged particle bunch propagating in plasma is subject to the self-modulation (SM) instability. We show that SM of a proton bunch can be seeded by the wakefields driven by a preceding electron bunch. SM timing reproducibility and control are at the level of a small fraction of the modulation period. With this seeding method, we independently control the amplitude of the seed wakefields with the charge of the electron bunch and the growth rate of SM with the charge of the proton bunch. Seeding leads to larger growth of the wakefields than in the instability case. A long, narrow, relativistic charged particle bunch propagating in plasma is subject to the self-modulation (SM) instability. We show that SM of a proton bunch can be seeded by the wakefields driven by a preceding electron bunch. SM timing reproducibility and control are at the level of a small fraction of the modulation period. With this seeding method, we independently control the amplitude of the seed wakefields with the charge of the electron bunch and the growth rate of SM with the charge of the proton bunch. Seeding leads to larger growth of the wakefields than in the instability case.

High resolution spectroscopy on the Tokamak à Configuration Variable (TCV) divertor plasma provided Doppler broadening measurements to infer the ion and neutral temperature of injected helium gas. This paper presents the Divertor Spectroscopy System’s (DSS) access to He II ion temperature measurements over a broad range, ≈0.5–15 eV, with an uncertainty of i(He II) ≃ T e, making this diagnostic a reliable thermometer along the divertor leg plasma over the wide range of magnetic equilibria and divertor configurations achievable in TCV. A detailed description of the diagnostic hardware, data analysis, and sources of uncertainty is presented.

We use a relativistic ionization front to provide various initial transverse wakefield amplitudes for the self-modulation of a long proton bunch in plasma. We show experimentally that, with sufficient initial amplitude ($\ge(4.1\pm0.4)$ MV/m), the phase of the modulation along the bunch is reproducible from event to event, with 3 to 7% (of 2$\pi$) rms variations all along the bunch. The phase is not reproducible for lower initial amplitudes. We observe the transition between these two regimes. Phase reproducibility is essential for deterministic external injection of particles to be accelerated., Comment: Letter and Supplemental Material, 6 figures, 8 pages

Helicon sources for NBIs -- - Helicon plasmas as negative ion sources could have advantages over traditional ICPs: - 1) reduced RF power; - 2) stable operation at low pressure (< 0.3 Pa) resulting in low electron stripping losses; - 3) higher efficiency of negative ion production in volume production mode, and a high degree of molecular dissociation, which would be favorable in a caesiated source; - 4) by producing a magnetized plasma column, they are well-adapted to a blade-shape geometry, such as those required for photo-neutralizer-based NBIs. -- RAID [1] is a high-power (up to 20kW) helicon source equipped with resonant antennas [2]-- - Helicon plasmas in hydrogen and deuterium can be produced and sustained in steady-state; - RAID plasmas exhibit a negative ion-rich shell; - The maximum negative ion density increases with injected RF power; -- A 1.5 D fluid model coupled to experimental Te and ne profiles reproduces many observed features -- - Negative ions are generated by dissociative attachment on ro-vibrationally excited H2 molecules; - In the plasma column center, hot electrons destroy H- by electron detachment and mutual neutralization. At the edge of the plasma column, atomic detachment destroys H-; -- Extraction of negative ions -- - A radial extractor has been developed; - First experiments demonstrated negative ion extraction.

Biogenous substances are increasingly important for modern therapies drug development. Due to allergic or toxic potential of single substances found in phytogenic extracts, availability of the active ingredient in its purest form is a prerequisite for application. In such context up­, downstream and fractionation processes are one major challenge for the up­scaling of bioconversion technologies, which are already successfully running at laboratory level. The further development and optimization of such procedures are hence a limiting factor for broad utilization of biomass as a sustainable alternative to fossil resources. Therefore, the research project to be introduced focuses on market oriented development and optimization of separation processes, as well as on their combination and scale up to industrial level., Proceedings of the 18th European Biomass Conference and Exhibition, 3-7 May 2010, Lyon, France, pp. 1461-1464