title: Magnetic flux braiding: Force-free equilibria and current sheets

authors: Longbottom, A.W.

subjects: MHD-plasmas-sun

abstract: We use a numerical, nonlinear, multigrid magnetic relaxation technique to investigate the generation of current sheets in three-dimensional magnetic flux braiding experiments. We are able to catalog the relaxed nonlinear force-free equilibria resulting from the application of deformations to an initially undisturbed region of plasma containing a uniform vertical magnetic field. The deformations are manifested by imposing motions on the bounding planes to which the magnetic field is anchored. Once imposed, the new distribution of magnetic footpoints are then taken to be fixed, so that the rest of the plasma must then relax to a new equilibrium configuration. For the class of footpoint motions that we have examined, we find that singular and nonsingular equilibria can be generated. By singular we mean that within the limits imposed by numerical resolution, we find that there is no convergence to a well-defined equilibrium as the number of grid points in the numerical domain is increased. These singular equilibria contain current “sheets” of ever increasing current intensity and decreasing width; they occur when the footpoint motions exceed a certain threshold and must include both twist and shear in order to be effective. On the basis of these results, we contend that flux braiding will indeed result in significant current generation. We discuss the implications of our results for coronal heating.

text: Magnetic flux braiding: Force-free equilibria and current sheets We use a numerical, nonlinear, multigrid magnetic relaxation technique to investigate the generation of current sheets in three-dimensional magnetic flux braiding experiments. We are able to catalog the relaxed nonlinear force-free equilibria resulting from the application of deformations to an initially undisturbed region of plasma containing a uniform vertical magnetic field. The deformations are manifested by imposing motions on the bounding planes to which the magnetic field is anchored. Once imposed, the new distribution of magnetic footpoints are then taken to be fixed, so that the rest of the plasma must then relax to a new equilibrium configuration. For the class of footpoint motions that we have examined, we find that singular and nonsingular equilibria can be generated. By singular we mean that within the limits imposed by numerical resolution, we find that there is no convergence to a well-defined equilibrium as the number of grid points in the numerical domain is increased. These singular equilibria contain current “sheets” of ever increasing current intensity and decreasing width; they occur when the footpoint motions exceed a certain threshold and must include both twist and shear in order to be effective. On the basis of these results, we contend that flux braiding will indeed result in significant current generation. We discuss the implications of our results for coronal heating.

year: 1998-06

title: Task-Based Language Teaching (TBLT): A Vietnamese case study using narrative frames to elicit teachers’ beliefs

authors: Barnard, Roger

subjects: Task-Based Language Teaching

abstract: Like many other methodological innovations, Task-Based Language Teaching (TBLT) has been applied to many English language curriculums across Asia. However, little research has been done to explore what teachers know and believe about these reforms in their specific contexts. This paper derives from an in-depth study of teacher cognition in Vietnamese high schools using multi-methods of data collection. It will present and discuss findings from one of the methods used to elicit teachers’ knowledge and attitudes - ‘narrative frames’ (Barkhuizen & Wette, 2008). Specifically, teachers were asked to write (in Vietnamese) reflective comments about their attitudes towards TBLT, and their recent experience of applying it in their classroom. After presenting some of the findings, the application and usefulness of this approach to data collection in relatable contexts will be considered.

text: Task-Based Language Teaching (TBLT): A Vietnamese case study using narrative frames to elicit teachers’ beliefs Like many other methodological innovations, Task-Based Language Teaching (TBLT) has been applied to many English language curriculums across Asia. However, little research has been done to explore what teachers know and believe about these reforms in their specific contexts. This paper derives from an in-depth study of teacher cognition in Vietnamese high schools using multi-methods of data collection. It will present and discuss findings from one of the methods used to elicit teachers’ knowledge and attitudes - ‘narrative frames’ (Barkhuizen & Wette, 2008). Specifically, teachers were asked to write (in Vietnamese) reflective comments about their attitudes towards TBLT, and their recent experience of applying it in their classroom. After presenting some of the findings, the application and usefulness of this approach to data collection in relatable contexts will be considered.

year: 2010

title: The TOHU framework: Sensing and interpreting tohu to heal from trauma

authors: McLachlan, A

subjects: Environment

abstract: This hypotheses article presents understandings and practices of tohu (signs) in the personal, eco-environmental, and spiritual wellbeing of Māori. Tohu can be observed in the natural, social, physical, or spiritual environment, and within a Māori worldview provide important ways of understanding and responding to phenomena. Wānanga (shared dialogue and debate) were held with seven Māori clinical psychologists from He Paiaka Tōtara (Māori Psychologist Network) and two mātauranga Māori specialists to explore their experiences, knowledge, and perspectives about tohu, with their insights collected through online information sharing. Our wānanga goals were to inform the creation of a therapeutic framework to address patu ngākau, psychological and spiritual trauma experienced by Māori. The results identified that tohu are located within the person and their environment, and the importance of exploring how tohu are interpreted. We propose a TOHU acronym as a framework for understanding and addressing the multifaceted impacts of patu ngākau.

text: The TOHU framework: Sensing and interpreting tohu to heal from trauma This hypotheses article presents understandings and practices of tohu (signs) in the personal, eco-environmental, and spiritual wellbeing of Māori. Tohu can be observed in the natural, social, physical, or spiritual environment, and within a Māori worldview provide important ways of understanding and responding to phenomena. Wānanga (shared dialogue and debate) were held with seven Māori clinical psychologists from He Paiaka Tōtara (Māori Psychologist Network) and two mātauranga Māori specialists to explore their experiences, knowledge, and perspectives about tohu, with their insights collected through online information sharing. Our wānanga goals were to inform the creation of a therapeutic framework to address patu ngākau, psychological and spiritual trauma experienced by Māori. The results identified that tohu are located within the person and their environment, and the importance of exploring how tohu are interpreted. We propose a TOHU acronym as a framework for understanding and addressing the multifaceted impacts of patu ngākau.

year: 2024