Ground-based gamma-ray astronomy has had a major breakthrough with the impressive results obtained using systems of imaging atmospheric Cherenkov telescopes. Ground-based gamma-ray astronomy has a huge potential in astrophysics, particle physics and cosmology. CTA is an international initiative to build the next generation instrument, with a factor of 5-10 improvement in sensitivity in the 100 GeV-10 TeV range and the extension to energies well below 100 GeV and above 100 TeV. CTA will consist of two arrays (one in the north, one in the south) for full sky coverage and will be operated as open observatory. The design of CTA is based on currently available technology. This document reports on the status and presents the major design concepts of CTA.

The Cherenkov Telescope Array (CTA) is a new observatory for very high-energy (VHE) gamma rays. CTA has ambitions science goals, for which it is necessary to achieve full-sky coverage, to improve the sensitivity by about an order of magnitude, to span about four decades of energy, from a few tens of GeV to above 100 TeV with enhanced angular and energy resolutions over existing VHE gamma-ray observatories. An international collaboration has formed with more than 1000 members from 27 countries in Europe, Asia, Africa and North and South America. In 2010 the CTA Consortium completed a Design Study and started a three-year Preparatory Phase which leads to production readiness of CTA in 2014. In this paper we introduce the science goals and the concept of CTA, and provide an overview of the project. ?? 2013 Elsevier B.V. All rights reserved

This study suggests that music therapy is effective in enhancing cognitive function and mental wellbeing and can be recommended as an alternative approach to manage AD associated symptoms.

The nature of the plasma wave modes around the ion kinetic scales in highly Alfvénic slow solar wind turbulence is investigated using data from the NASA's Parker Solar Probe taken in the inner heliosphere, at 0.18 Astronomical Unit (AU) from the sun. The joint distribution of the normalized reduced magnetic helicity σm (θRB, τ) is obtained, where θRB is the angle between the local mean magnetic field and the radial direction and τ is the temporal scale.Two populations around ion scales are identified: the first population has σm (θRB, τ) <0 for frequencies (in the spacecraft frame) ranging from 2.1 to 26 Hz for 60º < θRB < 130º, corresponding to kinetic Alfvén waves (KAWs), and the second population has σm (θRB, τ) >0 in the frequency range [1.4, 4.9] Hz for θRB > 150º, corresponding to Alfvén ion Cyclotron Waves (ACWs). This demonstrates for the first time the co-existence of KAWs and ACWs in the slow solar wind in the inner heliosphere, which contrasts with previous observations in the slow solar wind at 1 AU. This discrepancy between 0.18 and 1 AU could be explained, either by i) a dissipation of ACWs via cyclotron resonance during their outward journey, or by ii) the high Alfvénicity of the slow solar wind at 0.18AU that may be favorable for the excitation of ACWs.

Magnetic reconnection is an important phenomenon extensively existing in the interplanetary space and planetary magnetosphere, such as solar flares, solar and stellar coronae, solar wind, planetary magnetosphere, the interplanetary space, the interstellar medium, neutron start, accretion disks, astrophysical jets, galaxy clusters, and black holes. The traditional cognition is that the energy carried by the magnetic field comes to explosions through reconnection. Ultimately the energy converts to the particles'kinetic and thermal energy, resulting in the acceleration and heating of the ions and electrons (e.g.,

Magnetic reconnection is a very important physical process that converts magnetic energy into particle energy accompanied by the change of magnetic field topology, which is responsible for many explosive phenomena in space, astrophysical, and laboratory plasmas (

The scaling of the turbulent spectra provides a key measurement that allows us to discriminate between different theoretical predictions of turbulence. In the solar wind, this has driven a large number of studies dedicated to this issue using in situ data from various orbiting spacecraft. While a semblance of consensus exists regarding the scaling in the magnetohydrodynamic (MHD) and dispersive ranges, the precise scaling in the transition range and the actual physical mechanisms that control it remain open questions. Using the high-resolution data in the inner heliosphere from the Parker Solar Probe mission, we find that the sub-ion scales (i.e., at the frequency f ∼ [2, 9] Hz) follow a power-law spectrum f α with a spectral index α varying between −3 and −5.7. Our results also show that there is a trend toward an anticorrelation between the spectral slopes and the power amplitudes at the MHD scales, in agreement with previous studies: the higher the power amplitude the steeper the spectrum at sub-ion scales. A similar trend toward an anticorrelation between steep spectra and increasing normalized cross helicity is found, in agreement with previous theoretical predictions about the imbalanced solar wind. We discuss the ubiquitous nature of the ion transition range in solar wind turbulence in the inner heliosphere.

In the standard model of magnetic reconnection, both ions and electrons couple to the newly reconnected magnetic field lines and are ejected away from the reconnection diffusion region in the form of bidirectional burst ion/electron jets. Recent observations propose a new model: electron-only magnetic reconnection without ion coupling in an electron-scale current sheet. Based on the data from the Magnetospheric Multiscale (MMS) mission, we observe a long-extension inner electron diffusion region (EDR) at least 40 d i away from the X-line at the Earth’s magnetopause, implying that the extension of EDR is much longer than the prediction of the theory and simulations. This inner EDR is embedded in an ion-scale current sheet (the width of ∼4 d i, d i is ion inertial length). However, such ongoing magnetic reconnection was not accompanied with burst ion outflow, implying the presence of electron-only reconnection in an ion-scale current sheet. Our observations present a new challenge for understanding the model of standard magnetic reconnection and the electron-only reconnection model in an electron-scale current sheet.