title: Current singularities at finitely compressible three-dimensional magnetic null points

authors: Dmitruk, Pablo

subjects: mathematics

abstract: The formation of current singularities at line-tied two- and three-dimensional (2D and 3D, respectively) magnetic null points in a nonresistive magnetohydrodynamic environment is explored. It is shown that, despite the different separatrix structures of 2D and 3D null points, current singularities may be initiated in a formally equivalent manner. This is true no matter whether the collapse is triggered by flux imbalance within closed, line-tied null points or driven by externally imposed velocity fields in open, incompressible geometries. A Lagrangian numerical code is used to investigate the finite amplitude perturbations that lead to singular current sheets in collapsing 2D and 3D null points. The form of the singular current distribution is analyzed as a function of the spatial anisotropy of the null point, and the effects of finite gas pressure are quantified. It is pointed out that the pressure force, while never stopping the formation of the singularity, significantly alters the morphology of the current distribution as well as dramatically weakening its strength. The impact of these findings on 2D and 3D magnetic reconnection models is discussed.

text: Current singularities at finitely compressible three-dimensional magnetic null points The formation of current singularities at line-tied two- and three-dimensional (2D and 3D, respectively) magnetic null points in a nonresistive magnetohydrodynamic environment is explored. It is shown that, despite the different separatrix structures of 2D and 3D null points, current singularities may be initiated in a formally equivalent manner. This is true no matter whether the collapse is triggered by flux imbalance within closed, line-tied null points or driven by externally imposed velocity fields in open, incompressible geometries. A Lagrangian numerical code is used to investigate the finite amplitude perturbations that lead to singular current sheets in collapsing 2D and 3D null points. The form of the singular current distribution is analyzed as a function of the spatial anisotropy of the null point, and the effects of finite gas pressure are quantified. It is pointed out that the pressure force, while never stopping the formation of the singularity, significantly alters the morphology of the current distribution as well as dramatically weakening its strength. The impact of these findings on 2D and 3D magnetic reconnection models is discussed.

year: 2005-07-15

title: Review of Douglas Thomas, “Hacker Culture”

authors: Legg, Catherine

abstract: This article reviews the book '“Hacker Culture” by Douglas Thomas.

text: Review of Douglas Thomas, “Hacker Culture” This article reviews the book '“Hacker Culture” by Douglas Thomas.

year: 2005

title: He Paiaka Totara: Māori Psychologists Wānanga, report to Ngā Pae o te Māramatanga

authors: Waitoki, Waikaremoana

abstract: Sustainability for the growing number of Māori psychologists depends on a resilient system that reflects the centrality of Māori knowledge, tikanga, kawa and moemoea. Paiaka refers to whakapapa, identity, roots and connectedness. As Māori psychologists how we might use this term with Māori whānau and each other differs according to our own unique skills and abilities - our pūmanawa. (He Paiaka wānanga, August, 29, 2015).

text: He Paiaka Totara: Māori Psychologists Wānanga, report to Ngā Pae o te Māramatanga Sustainability for the growing number of Māori psychologists depends on a resilient system that reflects the centrality of Māori knowledge, tikanga, kawa and moemoea. Paiaka refers to whakapapa, identity, roots and connectedness. As Māori psychologists how we might use this term with Māori whānau and each other differs according to our own unique skills and abilities - our pūmanawa. (He Paiaka wānanga, August, 29, 2015).

year: 2016