Mass and magnetic field of eruptive solar filaments

I present a method for column density calculation of filament material seen in absorption in EUV wavelengths which utilises satellite data in a quasi-spectroscopic way. First, back-falling material following a particularly large eruption is examined and found to have column densities comparable with pre-eruption filaments (over 10^19 cm^−2), which is surprising since the filament material had been seen to expand by approximately two orders of magnitude. I then highlight morphology seen in the back-falling material consistent with the Rayleigh-Taylor instability (RTi) and estimate a characteristic magnetic field strength from equations governing the instability to be 0.6 G. Bubbles indicative of the RTi can also be seen developing into the bulk of the ejecta before breaking up and falling back. The growth rate of these bubbles is measured, and found to be larger than predicted by previous studies. Simulations of RT-unstable plasma are then conducted to investigate the effect of magnetic field strength on the development of the instability, which indicate that the development of the RTi is slower in plasmas with stronger magnetic fields embedded. When the observed growth rates were compared to that of the simulations, they were found to be a factor of five larger possibly due to outflows impacting the material, or that the material is not in fact stationary as the instability sets in. Finally, the column density calculation is refined by removing the noisy 94 Å channel and then applied to various portions of material involved in two unusual eruptions of an intermediate filament. The total hydrogen mass of the filament is estimated to be M_H = 2.4 × 10^15 g, and over half of this material appears to be lost in the second eruption

Plasma composition in a sigmoidal anemone active region

Using spectra obtained by the EIS instrument onboard Hinode, we present a detailed spatially resolved abundance map of an active region (AR)-coronal hole (CH) complex that covers an area of 359 arcsec x 485 arcsec. The abundance map provides first ionization potential (FIP) bias levels in various coronal structures within the large EIS field of view. Overall, FIP bias in the small, relatively young AR is 2-3. This modest FIP bias is a consequence of the AR age, its weak heating, and its partial reconnection with the surrounding CH. Plasma with a coronal composition is concentrated at AR loop footpoints, close to where fractionation is believed to take place in the chromosphere. In the AR, we found a moderate positive correlation of FIP bias with nonthermal velocity and magnetic flux density, both of which are also strongest at the AR loop footpoints. Pathways of slightly enhanced FIP bias are traced along some of the loops connecting opposite polarities within the AR. We interpret the traces of enhanced FIP bias along these loops to be the beginning of fractionated plasma mixing in the loops. Low FIP bias in a sigmoidal channel above the AR's main polarity inversion line where ongoing flux cancellation is taking place, provides new evidence of a bald patch magnetic topology of a sigmoid/flux rope configfiuration.Comment: For on-line animation, see http://www.mssl.ucl.ac.uk/~db2/fip_intensity.gif. Accepted by Ap

The positive soundscape project : a synthesis of results from many disciplines

This paper takes an overall view of ongoing findings from the Positive Soundscape Project, a large inter-disciplinary soundscapes study which is nearing completion. Qualitative fieldwork (soundwalks and focus groups) and lab-based listening tests have revealed that two key dimensions of the emotional response are calmness and vibrancy. In the lab these factors explain nearly 80% of the variance in listener response. Physiological validation is being sought using fMRI measurements, and these have so far shown significant differences in the response of the brain to affective and neutral soundscapes. A conceptual framework which links the key soundscape components and which could be used for future design is outlined. Metrics are suggested for some perceptual scales and possibilities for soundscape synthesis for design and user engagement are discussed, as are the applications of the results to future research and environmental noise policy

Coronal magnetic reconnection driven by CME expansion -- the 2011 June 7 event

Coronal mass ejections (CMEs) erupt and expand in a magnetically structured solar corona. Various indirect observational pieces of evidence have shown that the magnetic field of CMEs reconnects with surrounding magnetic fields, forming, e.g., dimming regions distant from the CME source regions. Analyzing Solar Dynamics Observatory (SDO) observations of the eruption from AR 11226 on 2011 June 7, we present the first direct evidence of coronal magnetic reconnection between the fields of two adjacent ARs during a CME. The observations are presented jointly with a data-constrained numerical simulation, demonstrating the formation/intensification of current sheets along a hyperbolic flux tube (HFT) at the interface between the CME and the neighbouring AR 11227. Reconnection resulted in the formation of new magnetic connections between the erupting magnetic structure from AR 11226 and the neighboring active region AR 11227 about 200 Mm from the eruption site. The onset of reconnection first becomes apparent in the SDO/AIA images when filament plasma, originally contained within the erupting flux rope, is re-directed towards remote areas in AR 11227, tracing the change of large-scale magnetic connectivity. The location of the coronal reconnection region becomes bright and directly observable at SDO/AIA wavelengths, owing to the presence of down-flowing cool, dense (10^{10} cm^{-3}) filament plasma in its vicinity. The high-density plasma around the reconnection region is heated to coronal temperatures, presumably by slow-mode shocks and Coulomb collisions. These results provide the first direct observational evidence that CMEs reconnect with surrounding magnetic structures, leading to a large-scale re-configuration of the coronal magnetic field.Comment: 12 pages, 12 figure

TURISMO EM ÁREAS RURAIS: SUAS POSSIBILIDADES E LIMITAÇÕES NO BRASIL

Neste trabalho, nosso interesse se orienta para o conjunto de atividades rurais não-agrícolas que denominamos de agroturismo, com o objetivo de analisar as possibilidades e limitações dessas atividades como alternativas e/ou formas complementares de geração de renda para os produtores agropecuários do País. O trabalho consta de três partes, além da introdução. A primeira procura trazer, através de um levantamento bibliográfico, o tratamento dado ao tema na literatura especializada. Na segunda, apresentamos algumas experiências relatadas no caso brasileiro e discutimos suas limitações e possibilidades enquanto uma atividade complementar de geração de renda e ocupação não-agrícola em áreas rurais no País. Na terceira parte, tratamos das políticas públicas relacionadas ao setor procurando mostrar que, infelizmente, não há ainda um conjunto coerente de iniciativas que configure uma política específica de turismo em áreas rurais no País. PALAVRAS-CHAVE: Turismo rural, atividades não-agrícolas, emprego rural. TOURISM IN RURAL AREAS: POSSIBILITIES AND LIMITATIONS IN BRAZIL This paper focus on a set of rural non-agricultural activities, called rural-tourism, analyzing the possibilities and limitations of these activities as alternatives and/or other complementary forms of generating income for agriculture and livestock producers in the country. The paper consists of three parts, besides the introduction. In the first one, the way the topic was dealt with in specialized publications is shown by a bibliographic survey. In the second part, some experiences related to the Brazilian case are presented, as well as its limitations and possibilities as a complementary activity for income generation, the non-agricultural occupation in rural areas of the country being also discussed. In the third part, the public policies related to the sector are dealt with, trying to show that unfortunately up to the present moment not a single set of coherent incentives has been presented in terms of building up a specific policy in terms of tourism for the rural areas of the country. KEYWORDS: Rural tourism, non-agricultural activities, rural employment. Publicação Online do Caderno CRH: http://www.cadernocrh.ufba.b

Perception of soundscapes : an interdisciplinary approach

This paper takes an overall view of findings from the Positive Soundscape Project, a large inter-disciplinary soundscapes study. Qualitative fieldwork (soundwalks and focus groups) have found that soundscape perception is influenced by cognitive effects such as the meaning of a soundscape and its components, and how information is conveyed by a soundscape, for example on the behaviour of people within the soundscape. Three significant clusters were found in the language people use to describe soundscapes: sound sources, sound descriptors and soundscape descriptors. Results from listening tests and soundwalks have been integrated to show that the two principal dimensions of soundscape emotional response seem to be calmness and vibrancy. Further, vibrancy seems to have two aspects: organisation of sounds and changes over time. The possible application of the results to soundscape assessment and design are briefly discussed