The Emergence of a Twisted Flux Tube into the Solar Atmosphere: Sunspot Rotations and the Formation of a Coronal Flux Rope

We present a 3D simulation of the dynamic emergence of a twisted magnetic flux tube from the top layer of the solar convection zone into the solar atmosphere and corona. It is found that after a brief initial stage of flux emergence during which the two polarities of the bipolar region become separated and the tubes intersecting the photosphere become vertical, significant rotational motion sets in within each polarity. The rotational motions of the two polarities are found to twist up the inner field lines of the emerged fields such that they change their orientation into an inverse configuration (i.e. pointing from the negative polarity to the positive polarity over the neutral line). As a result, a flux rope with sigmoid-shaped, dipped core fields form in the corona, and the center of the flux rope rises in the corona with increasing velocity as the twisting of the flux rope footpoints continues. The rotational motion in the two polarities is a result of propagation of non-linear torsional Alfv\'en waves along the flux tube, which transports significant twist from the tube's interior portion towards its expanded coronal portion. This is a basic process whereby twisted flux ropes are developed in the corona with increasing twist and magnetic energy, leading up to solar eruptions.Comment: 33 pages, 14 figures, Submitted to Ap

Twisted flux tube emergence from the convection zone to the corona II: Later states

3D simulations of magnetic flux emergence are carried out in a computational domain spanning the upper layers of the convection zone to the lower corona. We use the Oslo Staggered Code to solve the full MHD equations with non-grey and NLTE radiative transfer and thermal conduction along the magnetic field lines. In this paper we concentrate on the later stages of the simulations and study the evolution of the structure of the rising flux in the upper chromosphere and corona, the interaction between the emerging flux and the weak coronal magnetic field initially present, and the associated dynamics. The flux tube injected at the bottom boundary rises to the photosphere where it largely remains. However, some parts of the flux tube become unstable and expand in patches into the upper chromosphere. The flux rapidly expands towards the corona, pushing the coronal and transition region material aside, lifting and maintaining the transition region at heights greater than 5 Mm above the photosphere for extensive periods of time. The pre-existing magnetic field in the corona and transition region is perturbed by the incoming flux and reoriented by a series of high Joule heating events. Low density structures form in the corona while at later times a high density filamentary structure appears in the lower part of the expanding flux. The dynamics of these and other structures is discussed. While Joule heating due to the expanding flux is episodic, it increases in relative strength as fresh magnetic field rises and becomes energetically important in the upper chromosphere and corona at later times. Chromospheric, transition region and coronal lines are computed and their response to the perturbation caused by the expanding emerging flux is discussed.Comment: 31 pages, 12 figures, accepted in Ap

Building Capacity for Archives and Dissemination of Information in Uganda: A Case Study of Uganda Broadcasting Corporation and Directorate of Information

In today's information age, knowledge has become the gold standard. A great deal of information is being generated every day in central and local governments and this is likely to increase with the continued empowerment of the population. In Uganda the government has been for a long time committed towards building an integrated, self sustaining and independent national economy. For instance, there have been a number of attempts to enact laws and policies in Uganda regarding access to and protection of information including the National Records and Archives Act, 2001, the Access to Information Act, 2005, the Copyright and Neighbouring Rights Act, 2006, The Press and Journalist Statute, 1995, the Electronic Media Statute, 1995 and the Uganda Broadcasting Corporation Act, 2005. These laws been not properly utilised, nor have proper guidelines for building capacity for storage, archiving, utilisation, dissemination and use of information been put in place. Building capacity in any organisation requires considerable effort, covering restructuring systems, development of human resource and institutional capacity, and organisational structure. The aim of this study is to review the current state of the audiovisual records and materials in the Directorate of Information (DOI) and the Uganda Broadcasting Corporation (UBC), to provide a digitization strategy to enhance effective information dissemination in Uganda

Transitional justice and democratisation nexus: Challenges of confronting legacies of past injustices and promoting reconciliation within weak institutions in Kenya

Following the post-election violence (PEV) of 2007–8, which almost jettisoned the country into civil war, Kenya put in place a number of transitional justice mechanisms, such as truth telling, as a peacebuilding strategy. One of the major recommendations of Kenya’s Truth, Justice, and Reconciliation Commission (TJRC) is the creation of institutions and mechanisms for peacebuilding, reconciliation, and early warning with a view towards harmonising their activities and adopting a coordinated approach. This article explicates the centrality of democratic institutional reforms in the process of reconciliation, peacebuilding, and long-term stability. In tackling the notion of national reconciliation as a central pillar in post-conf lict recovery and peacebuilding, this paper proposes that reconciliation happens within strong and properly functioning institutions of governance that are supportive of transitional justice mechanisms. Based on the transitional justice process in Kenya and building upon a view of reconciliation as a process, rather than an end, this paper argues that strengthening institutions that function within governance structures will go a long way towards placing Kenya on the path to reconciliation, national cohesion, and long term stability. Keywords: Kenya, transitional justice, democratisation, reconciliation, institutional reforms, TJR

Persistent reservations in mining?

Includes bibliographical references.This paper analyses the persistence of colour bar reservations into the present day mining sector. Focusing on the occupations Banksman/Onsetter, Blaster, Engineer, Labourer and Winding Engine Driver, an ordered probit regression is run producing little evidence to support the persistence. A White skill bias is noted and further investigated using Oaxaca decomposition. Observable skill sets such as education, experience, demographics and firm level characteristics are unable to adequately explain the occupational gap between the races. This might suggests some skill based discrimination is still rife, however with various unobservable characteristics the model cannot control for; a causal relationship cannot be confidently concluded