Circular accelerator lattices are usually confined in the horizontal plane. Optics design does not rely on the orbit in the vertical direction. Here we propose a circular accelerator lattice in which ...the orbit moves in both horizontal and vertical directions. Having another degree of freedom, flexibility of the optics increases with less constraints of the orbit, e.g. a zero momentum compaction factor lattice without reverse bending magnets or a negative dispersion function. As a possible application of the concept, a collider ring arc of a muon collider facility is illustrated.
While a substorm involves auroral poleward expansion after initial brightening, a pseudosubstorm (pseudobreakup) subsides without progressing to poleward expansion. To understand what makes this ...difference, we studied near‐Earth magnetotail conditions at a pseudosubstorm onset and the subsequent substorm onset, using multipoint Time History of Events and Macroscale Interactions during Substorms spacecraft data. In the present event, near‐Earth magnetic reconnection possibly occurred before initial brightening for both pseudosubstorm and substorm. In the near‐Earth magnetotail at X ∼− 10 RE, the ion β, ion pressure, and ion and total (ion plus magnetic) pressure gradient projection along two closely located spacecraft were smaller and magnetic field lines were less stretched around the pseudosubstorm initial brightening than around the substorm initial brightening. Dipolarization did not occur for the pseudosubstorm, whereas it began just before poleward expansion for the substorm. These observations suggest that conditions of the near‐Earth magnetotail possibly affect whether the initial action develops into a full‐fledged substorm.
Plain Language Summary
A pseudosubstorm, also called pseudobreakup, is an auroral phenomenon very similar to a substorm but essentially differs in absence of active auroral expansion. In this paper, we studied conditions of the magnetotail at the beginning of these auroral phenomena on the basis of spacecraft observations. This comparison is expected to give us some clues to understanding of substorm triggering and development mechanisms. We found that plasma and magnetic field conditions in the magnetotail differed between the two auroral phenomena. This finding implies that magnetotail conditions possibly affect auroral development.
Key Points
We compared near‐Earth magnetotail conditions at a pseudosubstorm onset and the subsequent substorm onset
The pressure gradient and ion beta in the near‐Earth magnetotail were smaller for the pseudosubstorm than for the substorm
We suggest that near‐Earth magnetotail conditions possibly affect whether the initial action develops into a full‐fledged substorm
Equatorial noise (EN) emissions are observed inside and outside the plasmapause. EN emissions are referred to as magnetosonic mode waves. Using data from Van Allen Probes and Arase, we found ...conversion from EN emissions to electromagnetic ion cyclotron (EMIC) waves in the plasmasphere and in the topside ionosphere. A low‐frequency part of EN emissions becomes EMIC waves through branch splitting of EN emissions, and the mode conversion from EN to EMIC waves occurs around the frequency of M/Q = 2 (deuteron and/or alpha particles) cyclotron frequency. These processes result in plasmaspheric EMIC waves. We investigated the ion composition ratio by characteristic frequencies of EN emissions and EMIC waves and obtained ion composition ratios. We found that the maximum composition ratio of M/Q = 2 ions is ~10% below 3,000 km. The quantitative estimation of the ion composition will contribute to improving the plasma model of the deep plasmasphere and the topside ionosphere.
Plain Language Summary
Equatorial noise (EN) emissions are whistler mode waves. Using Van Allen Probe and Arase (ERG) plasma wave data, we found that EN emissions propagate toward the Earth and are converted to electromagnetic ion cyclotron (EMIC) waves in the deep plasmasphere and the topside ionosphere. We suggest that minor ions with a mass per charge (M/Q) = 2, that is, deuteron or alpha particles, play an important role in this process. The processes reported here are a new generation process of plasmaspheric EMIC waves. Moreover, we determined the ion composition ratio using characteristics of wave dispersion. We derived the altitude profile of the ion composition ratio and identified the maximum ratio of M/Q = 2 ions of about 10% in the deep plasmasphere.
Key Points
The first measurements of the conversion from equatorial noise to EMIC waves are presented
Existence of M/Q = 2 ions (deuteron or alpha particle) in the deep plasmasphere is essential to cause the conversion
The ion composition ratio is quantitatively estimated in the deep plasmasphere using characteristics of the wave dispersion
We present two Time History of Events and Macroscale Interactions during Substorms observations of whistler mode and electrostatic wave events in the innermost open boundary layer (IOBL), formed by ...dayside magnetopause reconnection. The IOBL is identified by high‐speed electrons from the magnetosheath on the magnetospheric side of the ion outflow from the reconnection site. Quasi‐parallel whistler mode waves propagating toward the reconnection region are observed, along with a partial shortage of magnetospheric electrons moving away from the reconnection region. Calculation of wave linear growth rates shows that the waves can be excited by the perpendicular electron temperature anisotropy that develops due to the partial shortage of field‐aligned magnetospheric electrons. Electrostatic waves close to the lower hybrid resonance frequency are observed in the IOBL in the second event, which occurred during the main phase of a magnetospheric storm. Magnetospheric electrons are almost completely lost in the event, except at pitch angles close to 90°, yet whistler mode waves are not observed. An electron beam from the magnetosheath and counterstreaming cold electrons originating from the plasmaspheric plume are observed in association with the electrostatic waves. Growth rate calculations show that the waves are likely to be ion acoustic waves excited via couplings between the flowing cold electrons and background cold ions. We suggest that differences in solar wind conditions and magnetic reconnection characteristics may control the shapes of the electron velocity distribution functions and the resulting plasma wave properties in the IOBL.
Key Points
Plasma waves are observed in the innermost open boundary layer formed by dayside magnetopause reconnection
Whistler mode waves are excited by electron temperature anisotropy due to the partial shortage of magnetospheric electrons
Ion acoustic waves may grow via instabilities between plasmaspheric electrons flowing toward the reconnection site and background cold ions
The compression behavior of deuterated ice VII and VIII was investigated by high pressure neutron scattering in the pressure range 2–13.7 GPa between 93 and 300 K. We establish equations of state ...which contain accurate values for the bulk moduli B0, their pressure derivatives B′0, as well as the ambient pressure volume V0. These equations of state hold over a large part of the stability domain of ice VII, by comparison with available x-ray data, and to at least ≈ 13 GPa for ice VIII. They are indistinguishable at low pressures, but beyond ≈ 7 GPa and at low temperatures ice VIII appears to become stiffer than expected. This might be related to an anomalous phonon hardening observed previously in ice VIII in this P/T range D. D. Klug et al., Phys. Rev. B 70, 144113 (2004).
In this paper we present the first quantitative measurement of the change in frequency (tune) with intensity of four transverse resonances in a high intensity Gaussian beam. Due to the nonlinear ...space charge forces present in high intensity beams, particle motion cannot be analytically described. Instead we use the simulator of particle orbit dynamics and the intense beam experiment, two linear Paul traps (LPTs), to replicate the system experimentally. In high intensity beams a coherent resonant response to both space charge and external field driven perturbations is possible, these coherent resonances are excited at a tune that differs by a factor Cm from that of the incoherent resonance. By increasing the number of ions stored in the LPT and studying the location of four different resonances we extract provisional values describing the change in tune of the resonance with intensity. These values are then compared to the Cm factors for coherent resonances. We find that the Cm factors do not accurately predict the location of resonances in high intensity Gaussian beams. Further insight into the experiment was gained through simulation using Warp, a particle-in-cell code.
Objectives
To determine whether interleukin‐6 (IL‐6) stimulates rat muscle satellite cell proliferation in culture, and if so, to clarify the signalling mechanisms.
Materials and methods
Primary ...satellite cells were isolated from thirty male F344 rats, 11 weeks of age. IL‐6 at concentrations of 0.01, 0.1, 1, 10 or 100 ng/ml was added to culture media.
Results
IL‐6 at 0.01–1 ng/ml induced dose‐dependent increase in cell proliferation. After treatment with 1 ng/ml IL‐6, cell proliferation increased by 31%, and p‐STAT3+/MyoD+ cells increased in number compared to those in control media (P < 0.05). Inhibitors of JAK2 (AG 490) and STAT3 (STAT3 peptide) blocked the increase in BrdUrd+ cell numbers at 6 h post stimulation with 1 ng/ml IL‐6 (P < 0.05). Furthermore, cyclin D1 mRNA expression and cyclin D1+/MyoD+ cell numbers significantly increased in cultures treated with 1 ng/ml IL‐6 compared to those in control media (P < 0.05). In contrast, treatment with 10 and 100 ng/ml IL‐6 did not stimulate cell proliferation. Treatment with 10 ng/ml IL‐6 induced greater SOCS3 mRNA expression than with 1 ng/ml IL‐6 and control media. Moreover, co‐localization of SOCS3 and myogenin was observed after treatment with 10 ng/ml IL‐6.
Conclusions
IL‐6 induced dose‐dependent increase in satellite cell proliferation by activating the JAK2/STAT3/cyclin D1 pathway.
Abstract
The intensity frontier has called for new initiatives in hadron accelerator design in order to accommodate space charge dominated beams. Octupoles are often used to damp beam instabilities ...caused by space charge, however the insertion of octupole magnets leads to a nonintegrable lattice which reduces the area of stable particle motion. One proposed solution is Quasi-Integrable optics (QIO), where the octupoles are inserted between sections of a specific lattice insertion called a T-insert. An octupole with a strength that scales as 1/
β
3
(s) is applied in the drift region, where the horizontal and vertical beta functions are equal, to create a time independent octupole field. This leads to a lattice with a time-independent Hamiltonian which is robust to small perturbations. IBEX is a Paul trap which allows the transverse dynamics of a collection of trapped particles to be studied, mimicking the propagation through multiple quadrupole lattice periods, whilst remaining stationary in the laboratory frame. In order to test QIO at the IBEX experiment, it has recently undergone an upgrade to allow for the creation of octupole fields. We present our design of the IBEX experiment upgrade along with simulation results of our proposed experiment to test QIO with space charge.
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