CSSP14, Sinaia, 25 th July, 2014 Space-atmospheric interactions of ultra-high energy Gina Isar isar@spacescience.ro cosmic rays
Outline Outline Cosmic rays: particles from outer space Earth is subject to a constant bombardment of subatomic particles that can reach energies far higher than the largest machines Astroparticle Physics & Atmospheric Physics Atmosphere as part of the AstroParticle Detectors CRs atmospheric interactions and effects Applications Conclusions
ILLUSTRATION OF CONSTANT BOMBARDMENT OF EARTH'S ATMOSPHERE BY COSMIC RADIATION If the rain of the intense cosmic radiation were visible to the human eye, the sky might appear to us as such
Victor Hess s discovery in 1912 Nobel Prize in Physics 1936
Scenes from a microworld Frothy wakes of subatomic particles recorded in a chamber of liquefied neon and hydrogen
Air shower measurements using the atmosphere as a detector From Argentinian Pampas (1.4km) (10 times the size of Bucharest) - Super-hybrid detector (SD+FD+R, including AMS) - Ultra-high energies (> 10 18 ev) See talks of A. Haungs Romania is full Auger Member! Pierre Auger Observatory From space (~400km) - In complement to Auger (FD+AMS) - Large FoV - Increased statistics - Extreme energies (>5x10 19 ev) See talk of M. Karus
Cosmic ray expertiments in the lab @CERN The Large Hadron Collider forward (LHCf) experiment - studying how collisions inside the LHC cause similar cascades of particles developed in the earth's atmosphere will help physicists to interpret and calibrate large-scale cosmic-ray experiments that can cover thousands of kilometres. The Cosmics Leaving Outdoor Droplets (CLOUD) experiment studying the link between galactic cosmic rays and cloud formation, using the cleanest box in the world, should contribute much to our fundamental understanding of aerosols and clouds, and their affect on climate.
Space - atmospheric interactions Cosmos-Geophysics (space weather, atmosphere, climatology etc.) CLOUD s finding: Ionisation from CRs ignificantly enhances aerosol formation CERN A possible link between CRs-Cloudcovers and Climate [Marsh & Svensmark 03] The highier solar activity the lower levels of cosmic rays the reduced cloud cover the increased global temperature
Applications Remote sensing: Monitoring the atmospheric environment from ground and space Remote sensing of night-time clouds is important for extracting shower information Satellite image processing: Exploitation of EO atmospheric images in support to validation of in-situ data Clouds interact with the radiation propagating through the atmosphere absorbing, reflecting and transmitting part of the energy Determine aerosols/clouds optical depth, cloud shapes, heights, and type Data mining: Exploration and blind analysis of large quantities of data in order to discover new knowledge
Conclusions Cosmic rays are present everywhere and always has been! There is much interest to promote interdisciplinary research of astroparticles!..when the resolution of a scientific problem requires knowledge and/or originating in another field. Astroparticle physicists need to know as much as possible about their detector, with the atmosphere being its biggest part: Astroparticle physics experiments, equipped with atmospheric monitoring infrastructures and located in unusual places, provide an opportunity to develop interdisciplinary activities, with atmospheric physics, chemistry, climatology, geology, seismology, planetary sciences, volcanology, marine biology, oceanography, glaciology, space weather and biology in extreme conditions. Think of synergies of cosmic rays!
THANK YOU! Acknowledgements "Minister of National Education, Programme for research - Space Technology and Advanced Research STAR, project number 83/2013 (Pilot study of ultra-high energy COsmic rays through their Space-Atmospheric interactions)" Referencies K. Louedec, Astropart. Phys. (2014), http://dx.doi.org/10.1016/j.astropartphys.2014.05.011 Kirkby, J. et al. Nature 476, 429-433 (2011) AtmoHEAD 2014 (Conference on: Atmospheric Monitoring for High Energy AstroParticles Detectors) http://www.appec.org (Astropart. Physics European Consortium) http://www.auger.org (Pierre Auger Observatory) Arxiv:1310.1641v1 Artist's impression of cosmic-ray shower over London
Glossary Cosmic Rays: are protons and atomic nuclei that travel across the Universe close to the speed of light. When these particles hit the upper atmosphere, they create a cascade of secondary particles, called an air shower. Fluorescence: is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence. Cherenkov light: the light emitted when a particle (such as a muon) passes through a medium at a speed greater than the phase velocity of light in that medium. The particle polarizes the molecules of that medium, which then turn back rapidly to their ground state, emitting radiation in the process. Energy measures: the energy unit in ApP is the electronvolt (ev). One ev is equivalent to 1.6 10 19 J. GeV (gigaelectronvolt) is equal to 1 billion ev and TeV (teraelectronvolt) is equal to 1,000 billion ev. These are the energy ranges most interesting to Astroparticle Physicists.
Understanding the atmosphere Space weather Since cosmic rays are propagating with a speed of light, one can foresee a magnetic storm on earth two days before it arrives. Low energy cosmic ray particles are used to study solar activity and space weather effects, such as Forbush-decreases (a rapid decrease in the observed galactic cosmic ray intensity following a coronal mass ejection, due to the magnetic field of the plasma solar wind sweeping some of the galactic cosmic rays away from Earth). Atmospheric monitoring Atmospheric state variables, like temperature, pressure, and humidity are mainly necessary for determining the fluorescence emission, but also for calculating the light transmission with respect to Rayleigh scattering. Atmospheric aerosol conditions are also measured, in order to describe the effect of Mie scattering in light transmission. Aerosols affect the quality of our life by influencing the Earth s radiation balance, directly through the scattering and absorption of solar radiation, and indirectly by acting as cloud condensation nuclei. Clouds are a major influence on the reconstruction of cosmic ray air showers by blocking the transmission of light, or enhancing the observed light flux due to multiple scattering of the intense Cherenkov light beam.