Recurrent and sporadic Forbush decreases during solar cycles 23–24

A comparison has been made between recurrent (associated with high-speed streams from coronal holes) and sporadic (caused by interplanetary coronal mass ejections (ICMEs)) Forbush decreases (FDs) in solar cycles 23 and 24 (as well as in the maxima of these cycles and the minimum between them). Forbush Effects and Interplanetary Disturbances database created and maintained in IZMIRAN provided a large number of events (about 1700 isolated FDs, among them 350 recurrent FDs, and 207 sporadic FDs selected with high reliability), which allowed us to apply statistical methods. The results revealed that sporadic FDs prevailed in the maxima of the cycles; recurrent FDs, in the minimum between the cycles. FD parameters (magnitude, decrease rate, anisotropy) are larger for sporadic events than for recurrent ones, especially in the maxima of the cycles. FD magnitude is greater in the maxima than in the minimum for sporadic events, and it changes weakly for recurrent ones. The solar wind velocity is on average greater for recurrent events than for sporadic ones; it is larger for recurrent FDs in the minimum and for sporadic FDs in the maxima. The magnetic field is stronger for sporadic FDs than for recurrent ones in the maxima and it is approximately equal for both types of events in the minimum. The magnetic field of ICMEs is weaker in the current solar cycle than in the previous one. The duration of the FD main phase is less in the maxima for both types of events; sporadic FDs developed significantly faster than recurrent ones in the maximum of cycle 23

Space weather and space anomalies

A large database of anomalies, registered by 220 satellites in different orbits over the period 1971–1994 has been compiled. For the first time, data from 49 Russian Kosmos satellites have been included in a statistical analysis. The database also contains a large set of daily and hourly space weather parameters. A series of statistical analyses made it possible to quantify, for different satellite orbits, space weather conditions on the days characterized by anomaly occurrences. In particular, very intense fluxes (>1000 pfu at energy >10MeV) of solar protons are linked to anomalies registered by satellites in high-altitude (>15 000 km), near-polar (inclination >55_) orbits typical for navigation satellites, such as those used in the GPS network, NAVSTAR, etc. (the rate of anomalies increases by a factor ~20), and to a much smaller extent to anomalies in geostationary orbits, (they increase by a factor ~4). Direct and indirect connections between anomaly occurrence and geomagnetic perturbations are also discussed

Different space weather effects in anomalies of the high and low orbital satellites

Preliminary results of the EU INTAS Project 00810, which aims to improve the methods of safeguarding satellites in the Earth's magnetosphere from the negative effects of the space environment, are presented. Anomaly data from the ‘‘Kosmos’’ series satellites in the period 1971–1999 are combined in one database, together with similar information on other spacecraft. This database contains, beyond the anomaly information, various characteristics of the space weather: geomagnetic activity indices (Ap, AE and Dst), fluxes and fluences of electrons and protons at different energies, high energy cosmic ray variations and other solar, interplanetary and solar wind data. A comparative analysis of the distribution of each of these parameters relative to satellite anomalies was carried out for the total number of anomalies (about 6000 events), and separately for high (~5000 events) and low (about 800 events) altitude orbit satellites. No relation was found between low and high altitude satellite anomalies. Daily numbers of satellite anomalies, averaged by a superposed epoch method around sudden storm commencements and proton event onsets for high (>1500 km) and low (<1500 km) altitude orbits revealed a big difference in a behavior. Satellites were divided on several groups according to the orbital characteristics (altitude and inclination). The relation of satellite anomalies to the environmental parameters was found to be different for various orbits that should be taken into account under developing of the anomaly frequency models. © 2004 COSPAR. Published by Elsevier Ltd. All rights reserved

ORCA (Antarctic Cosmic Ray Observatory): 2018 Latitudinal Survey

A set of detectors devoted to investigate secondary cosmic rays has performed a latitudinal observation from Vigo (Spain) to Juan Carlos I Spanish Antarctic Station (Livingston Island, Antarctic Peninsula) aboard the Sarmiento de Gamboa oceanographic vessel from November $14^{th}$ to January $2^{nd}$. The experiment is split into two modules, one composed by a stack of 3NM64, three BF3 bare counters (NEMO) and a muon telescope (MITO) with a mini neutron monitor in a $20^{\prime}$ maritime container on the Sarmiento de Gamboa$^{\prime}$s deck and a second module (TRISTAN) consisting of a set of 3 RPC planes with a lead layer in between the second and the third plane placed in a separate temperature controlled room below the ship$^{\prime}$s deck. The complete set of instruments is the Antarctic Cosmic Ray Observatory (ORCA) that has been be installed in the Juan Carlos I Spanish Antarctic Base in Livingston Island (Antarctica). The latitudinal survey took ORCA throughout the South Atlantic magnetic anomaly along the Brazilian coast. ORCA is able to measure fluxes of neutrons of different energies, charged particles (mostly muons) and muon incident directions on the detector surface. In this work, we present the preliminary results of the latitudinal survey