Aims. Detailed analysis of 11 transverse coronal loop oscillations in three events observed with the Atmospheric Imaging Assembly (AIA) instrument on board the Solar Dynamics Observatory (SDO) spacecraft. Detailed analysis includes analysis of the displacement time series, intensity variations and comparing EUVI and AIA data to estimate the 3D loop geometry. Methods. Time distance images extracted from cuts made perpendicular to the oscillations are obtained. A Gaussian plus background fitting technique is used to extract the time series which is then fitted with a damped cosine curve. Intensity variations are extracted along the time series points. EUVI/STEREO data is compared to AIA/SDO data to obtain three-dimensional models of the loop geometry.Results. Time series analysis revealed periods between 1.7 and 10 min and damping times between 2.9 and 13 min. Intensity variations are reliably observed for six of the loops and a comparison between EUVI/STEREO and AIA/SDO data is performed to simulate the polarisation of the kink mode. We conclude that the intensity variations are due to variations in the line of sight column depth of a horizontally polarised transverse loop oscillation. Coronal seismology of the kink mode was applied to determine the range of the internal Alfvén speed and the magnetic field strength for each loop.

Context. Observations show that transverse oscillations commonly occur in solar coronal loops. The rapid damping of these waves has been attributed to resonant absorption. The oscillation characteristics carries information of the structuring of the corona. However, self-consistent seismological methods that extract information from individual oscillations are limited because there are fewer observables than unknown parameters in the model, and the problem is underdetermined. Furthermore, it has been shown that one-to-one comparisons of the observed scaling of period and damping times with wave damping theories are misleading. Aims. We aim to investigate whether seismological information can be gained from the observed scaling laws in a statistical sense. Methods. A statistical approach is used whereby scaling laws are produced by forward modelling using distributions of values for key loop cross-sectional structuring parameters. We study two types of observations: 1) transverse loops oscillations as seen mainly with TRACE and SDO and 2) running transverse waves seen with the Coronal Multichannel Polarimeter (CoMP). Results. We demonstrate that the observed period-damping time scaling law does provide information about the physical damping mechanism, if observations are collected from as wide range of periods as possible and a comparison with theory is performed in a statistical sense. The distribution of the ratio of damping time over period, i.e. the quality factor, has been derived analytically and fitted to the observations. A minimum value for the quality factor of 0.65 has been found. From this, a constraint linking the ranges of possible values for the density contrast and inhomogeneity layer thickness is obtained for transverse loop oscillations. If the layer thickness is not constrained, then the density contrast is at most equal to 3. For transverse waves seen by CoMP, it is found that the ratio of maximum to minimum values for these two parameters has to be less than 2.06; i.e., the sampled values for the layer thickness and Alfvén travel time come from a relatively narrow distribution. Conclusions. Now that more and more transverse loop oscillations have been analysed, a statistical approach to coronal seismology becomes possible. Using the observed data cloud, we have found restrictions to the loop's density contrast and inhomogeneity layer thickness. Surprisingly, for running waves, narrow distributions for loop parameters have been found.

Probabilities for injecting protons into the radiation belts for large regions of B-L space by cosmic ray albedo neutron decay, Crand, and by solar proton albedo neutron decay, Spand, are computed. A computer program simulates the ejection of neutrons from the atmosphere of the earth. The computations are compared with both directional and omnidirectional experimental data. The trapped radiation belt protons with energies • 20 Mev can be explained by Crand injection and atmospheric losses only if the correct ratios of the albedo neutron fluxes to the mean atmospheric densities encountered by trapped protons are a factor of 50 larger than the values used in this paper. The trapped proton flux from Spand injection is evaluated using the currently estimated solar proton flux and found to be small compared with Crand injection. Below 20 Mev, in many regions of space, there are too many protons to be accounted for by either Crand or Spand injection, and some other source is required.

Two transversely oscillating coronal loops are investigated in detail during a flare on the 2011 September 6 using data from the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory. We compare two independent methods to determine the Alfvén speed inside these loops. Through the period of oscillation and loop length, information about the Alfvén speed inside each loop is deduced seismologically. This is compared with the Alfvén speed profiles deduced from magnetic extrapolation and spectral methods using AIA bandpass. We find that for both loops the two methods are consistent. Also, we find that the average Alfvén speed based on loop travel time is not necessarily a good measure to compare with the seismological result, which explains earlier reported discrepancies. Instead, the effect of density and magnetic stratification on the wave mode has to be taken into account. We discuss the implications of combining seismological, extrapolation, and spectral methods in deducing the physical properties of coronal loops.