In 1912, Victor Hess discovered cosmic rays in a series of balloon experiments. Since that time, cosmic ray physics has contributed to the knowledge in various fields of physical research, as subnuclear and elementary particle physics, astrophysics, plasma physics in specific conditions of space, and physics of solar-terrestrial relations. The first launches of spacecrafts of the space era identified various populations of energetic particles in space at energies slightly lower than the atmospheric threshold. Nowadays, cosmic ray physics includes experimental as well as theoretical studies in an extremely wide range of primary energies. The variability of the low-energy cosmic ray flux based on the observations mainly from the Earth and in its vicinity is one of the selected specific points of cosmic ray research to which the papers of the issue are aimed.

We invite investigators to contribute original research articles dealing with experiments, observations, data analysis, and modeling to advance our understanding of the cosmic ray (CR) variability both at short- (hour to days) and long-time scales (solar activity/magnetic cycles), and review articles that summarize the state of the art in this field and stimulate continuing efforts in research related to the variability of cosmic ray intensity and anisotropy could also be accepted. Potential topics include, but are not limited to:

• Cosmic ray modulation in the heliosphere
• Long- and midterm periodicities in CR intensity
• Contribution of heliospheric sources (solar flare particles, particles accelerated at interplanetary plasma shocks or turbulence, etc.)
• Ground-based observational techniques
• Satellite instruments for CR measurements
• Space-based observations of CR up to the heliosheath region
• Influence of the magnetosphere on the CR flux
• Relations of CR to atmospheric processes
• The role of CR observations in space weather research
• Tong-term cosmic ray variability and climate

Those of you considering submitting a research paper/review article may send an email with probable title to any of the editors as soon as possible, preferably before March 31, 2012. This will be helpful to us to organize the Special Issue in a better way.

Before submission authors should carefully read over the journal's Author Guidelines, which are located at http://www.hindawi.com/journals/aa/guidelines/. Prospective authors should submit an electronic copy of their complete manuscript through the journal Manuscript Tracking System at http://mts.hindawi.com/ according to the following timetable: