H-alpha features with hot onsets. II. A contrail fibril

The solar chromosphere observed in H-alpha consists mostly of narrow fibrils. The longest typically originate in network or plage and arch far over adjacent internetwork. We use data from multiple telescopes to analyze one well-observed example in a quiet area. It resulted from the earlier passage of an accelerating disturbance in which the gas was heated to high temperature as in the spicule-II phenomenon. After this passage a dark H-Halpha fibril appeared as a contrail. We use Saha-Boltzmann extinction estimation to gauge the onset and subsequent visibilities in various diagnostics and conclude that such H-alpha fibrils can indeed be contrail phenomena, not indicative of the thermodynamic and magnetic environment when they are observed but of more dynamic happenings before. They do not connect across internetwork cells but represent launch tracks of heating events and chart magnetic field during launch, not at present.Comment: Accepted for Astronomy & Astrophysic

On the multi-threaded nature of solar spicules

A dominant constituent in the dynamic chromosphere are spicules. Spicules at the limb appear as relatively small and dynamic jets that are observed to everywhere stick out. Many papers emphasize the important role spicules might play in the energy and mass balance of the chromosphere and corona. However, many aspects of spicules remain a mystery. In this Letter we shed more light on the multi-threaded nature of spicules and their torsional component. We use high spatial, spectral and temporal resolution observations from the Swedish 1-m Solar Telescope in the H{\alpha} spectral line. The data targets the limb and we extract spectra from spicules far out from the limb to reduce the line-of-sight superposition effect. We discover that many spicules display very asymmetric spectra with some even showing multiple peaks. To quantify this asymmetry we use a double Gaussian fitting procedure and find an average velocity difference between the single Gaussian components to be between 20-30 km s$^{-1}$ for a sample of 57 spicules. We observe that spicules show significant sub-structure where one spicule consists of many 'threads'. We interpret the asymmetric spectra as line-of-sight superposition of threads in one spicule and therefore have a measure for a perpendicular flow inside spicules which will be important for future numerical model to reproduce. In addition we show examples of {\lambda}-x-slices perpendicular across spicules and find spectral tilts in individual threads providing further evidence for the complex dynamical nature of spicules.Comment: Accepted by APJ Letter

Teelt en saldo van deder : Camelina sativa (deder) als alternatieve teelt

Deder is een ‘nieuw’ gewas voor de Nederlandse landbouw. Deder (Camelina Sativa (L.)) is een gewas dat vroeger al in Europa werd gebruikt. Momenteel wordt deder niet meer verbouwd. De hernieuwde interesse komt vooral voort uit de zoektocht naar perspectiefvolle oliehoudende energiegewassen. In verband met de sterke interesse als energiegewas is de energie- en broeikasgasbalans van deder bepaald. Hieruit blijkt dat deder, afhankelijk van zomer- of wintervariant, licht lager of licht beter scoort als winterkoolzaad

Assisting School Management Teams to construct their school improvement plans: an action learning approach

This article reports on a first cycle of a larger action research study conducted to determine how Circuit Teams could support School Management Teams of underperforming high schools towards whole-school development. Although it is a mandated requirement by the Department of Education, none of the four schools involved in the study had developed a school improvement plan, a necessary first step towards whole-school development. In this article we focus on the collaborative intervention we designed to meet the identified needs of the participants regarding the construction of a school improvement plan. A qualitative baseline study revealed the School Management Teams’ general disregard towards the school improvement plan as well as limited insight into what skills they needed to develop it, and their imperfect understanding of whole-school development. We explain the action research process we took to facilitate a clearer understanding of the school improvement plan and how to develop it. The data  analysis revealed that the collaborative learning experience ignited feelings of empowerment, increased motivation to collaborate with the Circuit Teams towards whole-school development, and generally assisted the School  Management Teams’ resolve to improve the management of their respective schools. These findings present  evidence that suggests the value of an action learning approach to the professional development of School Management Teams, but the process could be equally useful to encourage sustainable change in varied contexts of continued professional development.Keywords: Action learning, action research, Circuit Team, school improvement plan, School Management Team(s), school self-evaluation, systems theory approach, whole-school development, whole-school evaluation