from Frank Schulz

The open-access journal Living Reviews in Solar Physics has resumed publication with two more articles: “Large-scale Globally Propagating Coronal Waves” by Alexander Warmuth and “The Solar Cycle (major update)” by David H. Hathaway on September 18 and 21, 2015.

Please find the abstracts and further details below.

PUB.NO. lrsp-2015-3
Warmuth, Alexander
“Large-scale Globally Propagating Coronal Waves”

PUBLISHED: 2015-09-18

FULL ARTICLE: www.livingreviews.org/lrsp-2015-3

ABSTRACT:
Large-scale, globally propagating wave-like disturbances have been observed in the solar chromosphere and by inference in the corona since the 1960s. However, detailed analysis of these phenomena has only been conducted since the late 1990s. This was prompted by the availability of high-cadence coronal imaging data from numerous spaced-based instruments, which routinely show spectacular globally propagating bright fronts. Coronal waves, as these perturbations are usually referred to, have now been observed in a wide range of spectral channels, yielding a wealth of information. Many findings have supported the “classical” interpretation of the disturbances: fast-mode MHD waves or shocks that are propagating in the solar corona. However, observations that seemed inconsistent with this picture have stimulated the development of alternative models in which “pseudo waves” are generated by magnetic reconfiguration in the framework of an expanding coronal mass ejection. This has resulted in a vigorous debate on the physical nature of these disturbances. This review focuses on demonstrating how the numerous observational findings of the last one and a half decades can be used to constrain our models of large-scale coronal waves, and how a coherent physical understanding of these disturbances is finally emerging.

PUB.NO. lrsp-2015-4
Hathaway, David H.
“The Solar Cycle” (major update)

PUBLISHED: 2015-09-21

FULL ARTICLE: www.livingreviews.org/lrsp-2015-4

ABSTRACT:
The solar cycle is reviewed. The 11-year cycle of solar activity is characterized by the rise and fall in the numbers and surface area of sunspots. A number of other solar activity indicators also vary in association with the sunspots including; the 10.7 cm radio flux, the total solar irradiance, the magnetic field, flares and coronal mass ejections, geomagnetic activity, galactic cosmic ray fluxes, and radioisotopes in tree rings and ice cores. Individual solar cycles are characterized by their maxima and minima, cycle periods and amplitudes, cycle shape, the equatorward drift of the active latitudes, hemispheric asymmetries, and active longitudes. Cycle-to-cycle variability includes the Maunder Minimum, the Gleissberg Cycle, and the Gnevyshev–Ohl (even-odd) Rule. Short-term variability includes the 154-day periodicity, quasi-biennial variations, and double-peaked maxima. We conclude with an examination of prediction techniques for the solar cycle and a closer look at cycles 23 and 24.

UPCOMING ARTICLES AT:
solarphysics.livingreviews.org/Articles/upcoming.html