Ising Field Theory on a Pseudosphere

We show how the symmetries of the Ising field theory on a pseudosphere can be exploited to derive the form factors of the spin fields as well as the non-linear differential equations satisfied by the corresponding two-point correlation functions. The latter are studied in detail and, in particular, we present a solution to the so-called connection problem relating two of the singular points of the associated Painleve VI equation. A brief discussion of the thermodynamic properties is also presented.Comment: 39 pages, 6 eps figures, uses harvma

The ion motion in self-modulated plasma wakefield accelerators

The effects of plasma ion motion in self-modulated plasma based accelerators is examined. An analytical model describing ion motion in the narrow beam limit is developed, and confirmed through multi-dimensional particle-in-cell simulations. It is shown that the ion motion can lead to the early saturation of the self-modulation instability, and to the suppression of the accelerating gradients. This can reduce the total energy that can be transformed into kinetic energy of accelerated particles. For the parameters of future proton-driven plasma accelerator experiments, the ion dynamics can have a strong impact. Possible methods to mitigate the effects of the ion motion in future experiments are demonstrated.Comment: 11 pages, 3 figures, accepted for publication in Phys. Rev. Let

Spatial-temporal evolution of the current filamentation instability

The spatial-temporal evolution of the purely transverse current filamentation instability is analyzed by deriving a single partial differential equation for the instability and obtaining the analytical solutions for the spatially and temporally growing current filament mode. When the beam front always encounters fresh plasma, our analysis shows that the instability grows spatially from the beam front to the back up to a certain critical beam length; then the instability acquires a purely temporal growth. This critical beam length increases linearly with time and in the non-relativistic regime it is proportional to the beam velocity. In the relativistic regime the critical length is inversely proportional to the cube of the beam Lorentz factor $\gamma_{0b}$. Thus, in the ultra-relativistic regime the instability immediately acquires a purely temporal growth all over the beam. The analytical results are in good agreement with multidimensional particle-in-cell simulations performed with OSIRIS. Relevance of current study to recent and future experiments on fireball beams is also addressed

Partners in biodiversity science and policy

The development of standards, data sharing, and initiatives like the Global Biodiversity Information Facility and others have advanced research in many fields, including in conservation of biodiversity. Global assessments of extinction risk to species have been completed by IUCN for multiple taxa. The IUCN global assessments have had a major impact on conservation science and practice as well as biodiversity funding mechanisms though the Global Environment Facility, the World Bank, and the Critical Ecosystem Partnership Fund (CEPF). A signature of the assessments is a process of sustained interaction between conservation organizations and the research and academic community, effectively integrating science and policy on global scale. The model relies on several critical components: openness of the conservation community to scientific input and debate, engagement of the scientific community, conservation organization mediated data collation, and data sharing with ease of access. This model can be applied to other challenges to conserve biodiversity and assess how biodiversity loss affects the well-being of societies across the world. The recognition of the importance of biodiversity in meeting the Millennium Development Goals and the recognition of the failure to meet the 2010 Biodiversity Target illustrate the gap between what needs to be achieved and our current trajectory