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The project of the first Polish underground laboratory SUNLAB, in the Polkowice-Sieroszowice copper mine, belonging to the KGHM Polska Miedz S.A. holding, is presented. Two stages of the project are foreseen: SUNLAB1 (a small laboratory in the salt layer exhibiting extremely low level of natural radioactivity) and SUNLAB2 (a big laboratory in the anhydrite layer, able to host the next generation liquid argon detector-GLACIER, which is considered within the LAGUNA FP7 project). The results of the natural radioactivity background measurements performed in the Polkowice-Sieroszowice salt cavern are also briefly summarized. [ABSTRACT FROM AUTHOR]

Using high-resolution mass spectrometers on board the Advanced Composition Explorer (ACE), we surveyed the event-averaged ∼0.1–60 MeV/nuc heavy ion elemental composition in 64 large solar energetic particle (LSEP) events of cycle 23. Our results show the following: (1) The rare isotope 3He is greatly enhanced over the corona or the solar wind values in 46% of the events. (2) The Fe/O ratio decreases with increasing energy up to ∼10 MeV/nuc in ∼92% of the events and up to ∼60 MeV/nuc in ∼64% of the events. (3) Heavy ion abundances from C—Fe exhibit systematic M/Q-dependent enhancements that are remarkably similar to those seen in 3He-rich SEP events and CME-driven interplanetary (IP) shock events. Taken together, these results confirm the role of shocks in energizing particles up to ∼60 MeV/nuc in the majority of large SEP events of cycle 23, but also show that the seed population is not dominated by ions originating from the ambient corona or the thermal solar wind, as previously believed. Rather, it appears that the source material for CME-associated large SEP events originates predominantly from a suprathermal population with a heavy ion enrichment pattern that is organized according to the ion’s mass-per-charge ratio. These new results indicate that current LSEP models must include the routine production of this dynamic suprathermal seed population as a critical pre-cursor to the CME shock acceleration process. [ABSTRACT FROM AUTHOR]

We have surveyed He-Fe spectra for 41 Corotating Interaction Regions (CIRs) from 1998–2007 observed on ACE. The spectra are similar for all species, and have the form of broken power laws with the spectral break occurring at a few MeV/nucleon. Except for overabundances of He and Ne, the abundances are close to those of the solar wind. We find the rare isotope 3He is enhanced in ∼40% of the events. In individual CIRs the Fe/O ratio correlates strongly with the solar wind Fe/O ratio measured 2–4 days prior to the CIR passage. Taken together with previously reported observations of pick-up He+ in CIRs, these observations provide evidence that CIRs are accelerated out of a suprathermal ion pool of heated solar wind ions, pick-up ions, and remnant suprathermal ions from impulsive solar energetic particle (SEP) events. [ABSTRACT FROM AUTHOR]

Theoretical studies of particle acceleration by shocks have successfully modeled many observed features of the particle energy spectra and temporal variations; however, spectral slopes do not agree with in situ observations, and intensities show huge variations not explained by the models. Recent observations have shown that trace ions in the solar wind, such as 3He and He+, are present in the accelerated particles with enhanced abundances. The average heavy ion composition is also found to differ significantly from the solar wind. It is observed that these features correlate significantly with ambient suprathermal material abundances, giving evidence that the suprathermals are the seed population that is actually energized. This raises important new questions such as why the suprathermals are favored over the much more abundant solar wind. Since the suprathermal ion population has many more contributors, and much larger variability than the solar wind, this population needs much more detailed study to allow a closure of theory and observations in interplanetary space. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

The five large solar particle events during October–November 2003 presented an opportunity to test shock acceleration models with in-situ observations. We use solar particle spectra of H to Fe ions, measured by instruments on ACE, SAMPEX, and GOES-11, to investigate the Q/M-dependence of spectral breaks in the 28 October 2003 event. We find that the break energies scale as (Q/M)b with b ≤ 1.56 to 1.75, somewhat less than predicted. We also conclude that SEP spectra >100 MeV/nucleon are best fit by a double power-law shape. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

Coronal elemental abundances, as compared with abundances in the solar wind and solar energetic particles, provide the means for connecting solar wind gas with its coronal source. Comparison of coronal abundances with photospheric values shows fractionation with the ionization potential of the atom, providing important, though not yet fully understood, information about the exchange of material between corona and chromosphere. Fractionation due to gravitational settling provides clues about flows within the corona. In this paper, we discuss the uncertainties of abundance determinations with spectroscopic techniques and in situ measurements, we survey the ranges of abundance variations in both the corona and solar wind, and we discuss the progress in correlating solar wind features with their coronal sources. [ABSTRACT FROM AUTHOR]

We report energy spectra of He, O, and Fe nuclei, extending from ∼0.3 keV/nucleon to ∼300 MeV/nucleon, integrated over the period from the Fall of 1997 to mid-2000. These fluence measurements were made at 1 AU using data from the SWICS, ULEIS, SIS, and CRIS instruments on ACE, and include contributions from fast and slow solar wind, coronal mass ejections, pickup ions, impulsive and gradual solar particle events, acceleration in corotating interaction regions and other interplanetary shocks, and anomalous and galactic cosmic rays. Fluence measurements of six additional species are presented in the energy region from ∼0.04 to ∼100 MeV/nucleon. We discuss the relative contributions of the various particle components, and comment on the shape and time dependence of the measured energy spectra. [ABSTRACT FROM AUTHOR]

Using instrumentation on board the ACE spacecraft we describe short-time scale (∼3 hour) variations observed in the arrival profiles of ∼20 keV nucleon[sup -1] to ∼2 MeV nucleon[sup -1] ions from impulsive solar flares. These variations occurred simultaneously across all energies and were generally not in coincidence with any local magnetic field or plasma signature. These features appear to be caused by the convection of magnetic flux tubes past the observer that are alternately filled and devoid of flare ions even though they had a common flare source at the Sun. In these particle events we therefore have a means to observe and measure the mixing of the interplanetary magnetic field due to random walk. In a survey of 25 impulsive flares observed at ACE between 1997 November and 1999 July these features had an average time scale of 3.2 hours, corresponding to a length of ∼0.03 AU. The changing magnetic connection to the flare site sometimes lead to an incomplete observation of a flare at 1 AU; thus the field-line mixing is an important effect in studies of impulsive flare energy spectra. [ABSTRACT FROM AUTHOR]

We have addressed the problem of the discrepancy between observations of solar cosmic rays, often showing sharp-gradients, and observations of galactic and anomalous cosmic rays which are consistent with the diffusive-transport description. We have carried out numerical simulations of the propagation of energetic charged particles in a turbulent magnetic field similar to that observed in the solar wind. If the particles are released impulsively near the sun, in a region small compared with the field coherence scale (a solar flare, for example), they exhibit characteristic fluctuations in intensity at 1 AU (dropouts), associated with very-steep localized gradients. The field coherence scale near the sun is the size of a supergranulation cell, and is about 0.01 AU at the orbit of Earth. These numerical simulations are quantitatively very similar to recent observations by the ACE spacecraft. These fluctuations occur naturally as part of the particle transport in the same field which results in large-scale cross-field diffusion and which has previously been used to study the propagation of CIR-associated particles to high heliographic latitudes. [ABSTRACT FROM AUTHOR]

Impulsive solar energetic particle (SEP) events are associated with impulsive X-ray flares, energetic electrons, and enhanced heavy ion abundances. Using instrument on ACE, we examine the onset and ion's pathlength for an impulsive SEP in May 2000. By assuming zero degree pitch-angle scattering, we fit the minimum ion's path-length and compare that with the nominal Parker spiral length. We found a small difference between the two path-lengths, with the fitted path-length 10% longer. We believe the difference can be due to ions traveling along the magnetic field with a finite pitch angle distribution, and/or from paths differing from the nominal Parker spiral configuration. The event is also found to have a close association with solar metric Type III radio bursts. [ABSTRACT FROM AUTHOR]