Travelling solitons in the parametrically driven nonlinear Schroedinger equation

We show that the parametrically driven nonlinear Schroedinger equation has wide classes of travelling soliton solutions, some of which are stable. For small driving strengths nonpropogating and moving solitons co-exist while strongly forced solitons can only be stably when moving sufficiently fast.Comment: The paper is available as the JINR preprint E17-2000-147(Dubna, Russia) and the preprint of the Max-Planck Institute for the Complex Systems mpipks/0009011, Dresden, Germany. It was submitted to Physical Review

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

Restoring Hope for Syrian Refugees: Social Support Students Need to Excel at School

This qualitative, phenomenological case study was designed to elicit Syrian refugee students’ perceptions regarding the individuals who provide them with the social support needed for academic success. Semi-structured interviews were conducted with 10 male Syrian eighth graders at a public middle school in Lebanon. House\u27s social support framework guided this study and served as the theoretical lens through which data were collected and analysed. Findings from this study revealed teachers, supervisors, and administrators as expected major providers of the social supports that Syrian refugee students need to excel in their studies. However, when students do not find support where they might expect it to be, they adopt coping strategies such as independence, perseverance, self-efficacy, and peer-teaching. These findings are of primary importance to school administrators, humanitarian aid agencies, and policymakers. The article concludes with recommendations for practice and future research