Viral to metazoan marine plankton nucleotide sequences from the Tara Oceans expedition

A unique collection of oceanic samples was gathered by the Tara Oceans expeditions (2009–2013), targeting plankton organisms ranging from viruses to metazoans, and providing rich environmental context measurements. Thanks to recent advances in the field of genomics, extensive sequencing has been performed for a deep genomic analysis of this huge collection of samples. A strategy based on different approaches, such as metabarcoding, metagenomics, single-cell genomics and metatranscriptomics, has been chosen for analysis of size-fractionated plankton communities. Here, we provide detailed procedures applied for genomic data generation, from nucleic acids extraction to sequence production, and we describe registries of genomics datasets available at the European Nucleotide Archive (ENA, www.ebi.ac.uk/ena). The association of these metadata to the experimental procedures applied for their generation will help the scientific community to access these data and facilitate their analysis. This paper complements other efforts to provide a full description of experiments and open science resources generated from the Tara Oceans project, further extending their value for the study of the world’s planktonic ecosystems

Viral to metazoan marine plankton nucleotide sequences from the Tara Oceans expedition

A unique collection of oceanic samples was gathered by the Tara Oceans expeditions (2009-2013), targeting plankton organisms ranging from viruses to metazoans, and providing rich environmental context measurements. Thanks to recent advances in the field of genomics, extensive sequencing has been performed for a deep genomic analysis of this huge collection of samples. A strategy based on different approaches, such as metabarcoding, metagenomics, single-cell genomics and metatranscriptomics, has been chosen for analysis of size-fractionated plankton communities. Here, we provide detailed procedures applied for genomic data generation, from nucleic acids extraction to sequence production, and we describe registries of genomics datasets available at the European Nucleotide Archive (ENA, www.ebi.ac.uk/ena). The association of these metadata to the experimental procedures applied for their generation will help the scientific community to access these data and facilitate their analysis. This paper complements other efforts to provide a full description of experiments and open science resources generated from the Tara Oceans project, further extending their value for the study of the world's planktonic ecosystems

THE DRIFT SOURCE : A NEGATIVE ION SOURCE MODULE FOR DC MULTI-AMPERES ION BEAMS

International audienceThe concept of a modular large size ion source is under investigation in our laboratory for the development of the very intense (tens of amperes) negative ion (D-) beams needed for neutral beam injection in Thermonuclear Fusion Research. The basic idea is to develop a compact small ion source producing the required ion flux (20-30mA/cm 2) over a total surface of about 200cm 2 and designed in such a way that it can easily juxtaposed with other identical modules. A large negative ion source of any size (up to several m 2) and shape could be realised as a set of several modules. The anticipated advantage of this concept is the minimisation of the risk inherent in a large extrapolation in size (e.g. »1.0m 2 for ITER) of the present ion sources. In this context, we have developed and tested a source module, called the DRIFT source, whose main properties are presented in this paper. The particular magnetic field configuration of this module ensures, in a simplified way, a very good plasma confinement allowing operation of the source at very low filling pressures. Up to now, a Dcurrent of 1A (20mA/cm 2) 50keV energy, 1s pulse length, was obtained with Caesium vapour seeding at 0.15Pa source pressure with an arc power of 2.5kW/litre (12kW)

Developing high performance RF heating scenarios on the WEST tokamak

International audienceHigh power experiments, up to 9.2 MW with LHCD and ICRH, have been carried out in the full tungsten tokamak WEST. Quasi non inductive discharges have been achieved allowing to extend the plasma duration to 53s at medium density (ne=3.7×10 19 m-3). Apart few pulses post-boronization, the plasma radiation is rather high (Prad/Ptot~50%) and is dominated by W. This fraction does not vary as the RF power is ramped up and, against expectations, it is quite similar in ICRH and/or LHCD heated plasmas. Hot L mode plasmas (Te(0)>3keV) with a confinement time following the ITER L96 scaling are routinely obtained, confirming the weak aspect ratio dependence of this scaling law. Tungsten accumulation is generally not an operational issue on WEST. Nonetheless, 25% of the of the discharges are affected by a rapid collapse of the central electron temperature which occurs when a slight decrease of Te leads to enhanced radiation causing flat or hollow current profiles. To this respect LHCD-only discharges are compared to ICRH and ICRH/LHCD discharges

Developing high performance RF heating scenarios on the WEST tokamak

International audienceHigh power experiments, up to 9.2 MW with LHCD and ICRH, have been carried out in the full tungsten tokamak WEST. Quasi non inductive discharges have been achieved allowing to extend the plasma duration to 53s at medium density (ne=3.7×10 19 m-3). Apart few pulses post-boronization, the plasma radiation is rather high (Prad/Ptot~50%) and is dominated by W. This fraction does not vary as the RF power is ramped up and, against expectations, it is quite similar in ICRH and/or LHCD heated plasmas. Hot L mode plasmas (Te(0)>3keV) with a confinement time following the ITER L96 scaling are routinely obtained, confirming the weak aspect ratio dependence of this scaling law. Tungsten accumulation is generally not an operational issue on WEST. Nonetheless, 25% of the of the discharges are affected by a rapid collapse of the central electron temperature which occurs when a slight decrease of Te leads to enhanced radiation causing flat or hollow current profiles. To this respect LHCD-only discharges are compared to ICRH and ICRH/LHCD discharges

Developing high performance RF heating scenarios on the WEST tokamak

International audienceHigh power experiments, up to 9.2 MW with LHCD and ICRH, have been carried out in the full tungsten tokamak WEST. Quasi non inductive discharges have been achieved allowing to extend the plasma duration to 53s at medium density (ne=3.7×10 19 m-3). Apart few pulses post-boronization, the plasma radiation is rather high (Prad/Ptot~50%) and is dominated by W. This fraction does not vary as the RF power is ramped up and, against expectations, it is quite similar in ICRH and/or LHCD heated plasmas. Hot L mode plasmas (Te(0)>3keV) with a confinement time following the ITER L96 scaling are routinely obtained, confirming the weak aspect ratio dependence of this scaling law. Tungsten accumulation is generally not an operational issue on WEST. Nonetheless, 25% of the of the discharges are affected by a rapid collapse of the central electron temperature which occurs when a slight decrease of Te leads to enhanced radiation causing flat or hollow current profiles. To this respect LHCD-only discharges are compared to ICRH and ICRH/LHCD discharges

Developing high performance RF heating scenarios on the WEST tokamak

International audienceHigh power experiments, up to 9.2 MW with LHCD and ICRH, have been carried out in the full tungsten tokamak WEST. Quasi non inductive discharges have been achieved allowing to extend the plasma duration to 53s at medium density (ne=3.7×10 19 m-3). Apart few pulses post-boronization, the plasma radiation is rather high (Prad/Ptot~50%) and is dominated by W. This fraction does not vary as the RF power is ramped up and, against expectations, it is quite similar in ICRH and/or LHCD heated plasmas. Hot L mode plasmas (Te(0)>3keV) with a confinement time following the ITER L96 scaling are routinely obtained, confirming the weak aspect ratio dependence of this scaling law. Tungsten accumulation is generally not an operational issue on WEST. Nonetheless, 25% of the of the discharges are affected by a rapid collapse of the central electron temperature which occurs when a slight decrease of Te leads to enhanced radiation causing flat or hollow current profiles. To this respect LHCD-only discharges are compared to ICRH and ICRH/LHCD discharges

Initial Results from Boron Powder Injection Experiments in WEST Lower Single Null L-mode Plasmas

Using a recently installed impurity powder dropper (IPD), boron powder (< 150 μm) was injected into lower single null (LSN) L-mode discharges in WEST. IPDs possibly enable real-time wall conditioning of the plasma-facing components and may help to facilitate H-mode access in the full-tungsten environment of WEST. The discharges in this experiment featured Ip = 0.5 MA, BT = 3.7 T, q95 = 4.3, tpulse = 12–30 s, ne,0 ~ 4×1019 m-2, and PLHCD ~ 4.5 MW. Estimates of the deuterium and impurity particle fluxes, derived from a combination of visible spectroscopy measurements and their corresponding S/XB coefficients, showed decreases of ~ 50% in O+, N+, and C+ populations during powder injection and a moderate reduction of these low-Z impurities (~ 50%) and W (~ 10%) in the discharges that followed powder injection. Along with the improved wall conditions, WEST discharges with B powder injection observed improved confinement, as the stored energy WMHD, neutron rate, and electron temperature Te increased significantly (10–25% for WMHD and 60–200% for the neutron rate) at constant input power. These increases in confinement scale up with the powder drop rate and are likely due to the suppression of ion temperature gradient (ITG) turbulence from changes in Zeff and/or modifications to the electron density profile.README.txt should be consulted for table of contents information

Viral to metazoan marine plankton nucleotide sequences from the Tara Oceans expedition

A unique collection of oceanic samples was gathered by the Tara Oceans expeditions (2009-2013), targeting plankton organisms ranging from viruses to metazoans, and providing rich environmental context measurements. Thanks to recent advances in the field of genomics, extensive sequencing has been performed for a deep genomic analysis of this huge collection of samples. A strategy based on different approaches, such as metabarcoding, metagenomics, single-cell genomics and metatranscriptomics, has been chosen for analysis of size-fractionated plankton communities. Here, we provide detailed procedures applied for genomic data generation, from nucleic acids extraction to sequence production, and we describe registries of genomics datasets available at the European Nucleotide Archive (ENA, www.ebi.ac.uk/ena). The association of these metadata to the experimental procedures applied for their generation will help the scientific community to access these data and facilitate their analysis. This paper complements other efforts to provide a full description of experiments and open science resources generated from the Tara Oceans project, further extending their value for the study of the world's planktonic ecosystems.status: publishe

Viral to metazoan marine plankton nucleotide sequences from the Tara Oceans expedition

International audienc