Multiwavelength studies of MHD waves in the solar chromosphere: An overview of recent results

The chromosphere is a thin layer of the solar atmosphere that bridges the relatively cool photosphere and the intensely heated transition region and corona. Compressible and incompressible waves propagating through the chromosphere can supply significant amounts of energy to the interface region and corona. In recent years an abundance of high-resolution observations from state-of-the-art facilities have provided new and exciting ways of disentangling the characteristics of oscillatory phenomena propagating through the dynamic chromosphere. Coupled with rapid advancements in magnetohydrodynamic wave theory, we are now in an ideal position to thoroughly investigate the role waves play in supplying energy to sustain chromospheric and coronal heating. Here, we review the recent progress made in characterising, categorising and interpreting oscillations manifesting in the solar chromosphere, with an impetus placed on their intrinsic energetics.Comment: 48 pages, 25 figures, accepted into Space Science Review

A search for resonances decaying into a Higgs boson and a new particle X in the XH → qqbb final state with the ATLAS detector

A search for heavy resonances decaying into a Higgs boson (H) and a new particle (X) is reported, utilizing 36.1 fb−1 of proton–proton collision data at collected during 2015 and 2016 with the ATLAS detector at the CERN Large Hadron Collider. The particle X is assumed to decay to a pair of light quarks, and the fully hadronic final state is analysed. The search considers the regime of high XH resonance masses, where the X and H bosons are both highly Lorentz-boosted and are each reconstructed using a single jet with large radius parameter. A two-dimensional phase space of XH mass versus X mass is scanned for evidence of a signal, over a range of XH resonance mass values between 1 TeV and 4 TeV, and for X particles with masses from 50 GeV to 1000 GeV. All search results are consistent with the expectations for the background due to Standard Model processes, and 95% CL upper limits are set, as a function of XH and X masses, on the production cross-section of the resonance

Tritium management in fusion synfuel designs

Two blanket types are being studied: a lithium-sodium pool boiler and a lithium-oxide- or lithium-sodium pool boiler and a lithium-oxide- or aluminate-microsphere moving bed. For each, a wide variety of current technology was considered in handling the tritium. Here, we show the pool boiler with the sulfur-iodine thermochemical cycle first developed and now being piloted by the General Atomic Company. The tritium (T/sub 2/) will be generated in the lithium-sodium mixture where the concentration is approx. 10 ppM and held constant by a scavenging system consisting mainly of permeators. An intermediate sodium loop carries the blanket heat to the thermochemical cycle, and the T/sub 2/ in this loop is held to 1 ppM by a similar scavenging system. With this design, we have maintained blanket inventory at 1 kg of tritium, kept thermochemical cycle losses to 5 Ci/d and environmental loss to 10 Ci/d, and held total plant risk inventory at 7 kg tritium

Scoping of fusion-driven retorting of oil shale

In the time frame beyond 2005, fusion reactors are likely to make their first appearance when the oil shale industry will probably be operating with 20% of the production derived from surface retorts operating on deep mined shale from in situ retorts and 80% from shale retorted within these in situ retorts using relatively fine shale uniformly rubblized by expensive mining methods. A process was developed where fusion reactors supply a 600/sup 0/C mixture of nitrogen, carbon dioxide, and water vapor to both surface and in situ retorts. The in situ production is accomplished by inert gas retorting, without oxygen, avoiding the burning of oil released from the larger shale particles produced in a simpler mining method. These fusion reactor-heated gases retort the oil from four 50x50x200m in-situ rubble beds at high rate of 40m/d and high yield (i.e., 95% F.A.), which provided high return on investment around 20% for the syncrude selling at $20/bbl, or 30$30/bbl for heating oil. The bed of 600/sup 0/C retorted shale, or char, left behind was then burned by the admission of ambient air in order to recover all of the possible energy from the shale resource. The hot combustion gases, mostly nitrogen, carbon dioxide and water vapor are then heat-exchanged with fusion reactor blanket coolant flow to be sequentially introduced into the next rubble bed ready for retorting. The advantages of this fusion-driven retorting process concept are a cheaper mining method, high yield and higher production rate system, processing with shale grades down to 50 l/mg (12 gpt), improved resource recovery by complete char utilization and low energy losses by leaving behind a cold, spent bed

Tritium management in fusion reactors

This is a review paper covering the key environmental and safety issues and how they have been handled in the various magnetic and inertial confinement concepts and reference designs. The issues treated include: tritium accident analyses, tritium process control, occupational safety, HTO formation rate from the gas-phase, disposal of tritium contaminated wastes, and environmental impact--each covering the Joint European Tokamak (J.E.T. experiment), Tokamak Fusion Test Reactor (TFTR), Russian T-20, The Next Step (TNS) designs by Westinghouse/ORNL and General Atomic/ANL, the ANL and ORNL EPR's, the G.A. Doublet Demonstration Reactor, the Italian Fintor-D and the ORNL Demo Studies. There are also the following full scale plant reference designs: UWMAK-III, LASL's Theta Pinch Reactor Design (RTPR), Mirror Fusion Reactor (MFR), Tandem Mirror Reactor (TMR), and the Mirror Hybrid Reactor (MHR). There are four laser device breakeven experiments, SHIVA-NOVA, LLL reference designs, ORNL Laser Fusion power plant, the German ''Saturn,'' and LLL's Laser Fusion EPR I and II

Interfacing the tandem mirror reactor to the sulfur-iodine process for hydrogen production

The blanket is linked to the H/sub 2/SO/sub 4/ vaporization units and SO/sub 3/ decomposition reactor with either sodium or helium. The engineering and safety problems associated with these choices are discussed. This H/sub 2/SO/sub 4/ step uses about 90% of the TMR heat and is best close-coupled to the nuclear island. The rest of the process we propose to be driven by steam and does not require close-coupling. The sodium loop coupling seems to be preferable at this time. We can operate with a blanket around 1200 K and the SO/sub 3/ decomposer around 1050 K. This configuration offers double-barrier protection between Li-Na and the SO/sub 3/ process gases. Heat pipes offer an attractive alternate to provide an additional barrier, added modularity for increased reliability, and tritium concentration and isolation operations with very little thermal penalty

Tritium handling in the Mirror Fusion Hybrid Reactor

A reference design study for a Mirror Fusion Hybrid Reactor has been completed which examines the tritium handling problems. Breeding pins composed of aluminum alloys contain lithium hydride with a four-year residence time for tritium production. The slip-stream helium tritium capture system is designed to handle a 0.1 percent pin failure and will reduce environmental losses to below 3 Ci/day. The neutral beam injectors and direct converters utilize small, thin electrode tubes at 700/sup 0/C for accelerating the deuterium or tritium, and they will by triton implantation permeate about 3 x 10/sup 5/ Ci/day into the internal helium coolant flow. A capture system will reduce these losses to 6 Ci/day, combined. The reactor hall is designed with a low humidity, air atmosphere which is continuously processed in order to handle leakage and permeability losses from the nuclear island at 180 Ci/day while still maintaining levels of tritium below MPC. The precessor is also able to handle severe accidental releases of tritium at the 26 kilogram level and permit worker re-entry (with ventilated suits) in a matter of about one week. These approaches to fusion power plant are found to be technically feasible today and economically attractive