20.500.12556/RUNG-4739-b15a2218-a753-0a59-945a-38d439820fce
Space weather research with the Pierre Auger Observatory
Raziskave vesoljskega vremena z observatorijem Pierre Auger
Space weather refers to environmental conditions in the interplanetary space and Earth’s
magnetosphere, ionosphere and exosphere and can influence the performance and reliability
of electronics based technological systems. The major role in space weather
changes plays the solar wind, a stream of charged particles (mostly electrons and protons)
with energies of approximately 1 keV, that can cause geomagnetic storms and auroras.
During their entry into the atmosphere, high energy cosmic rays collide with atomic
nuclei of atmospheric gasses. When scattering occurs extensive air showers are created.
Those cascades of secondary particles create flashes of light due to the Cherenkov
effect as well as excite molecules of nitrogen gas in atmosphere, which then glow in
fluorescent light. In order to observe the light created by air showers, it has to be
collected with telescopes. The particles from the cascades that reach ground can be
detected with surface detectors. The Pierre Auger Observatory is the largest observatory
for cosmic ray measurements. It is located in Argentinian pampas covering an area of
3000 km2. It consists of 1660 surface detectors and 27 fluorescence telescopes. For
cosmic rays with energies above few 1017 eV, a precise reconstruction of energy and
direction of primary particle is achievable. Observatory also allows measurement of
flux of incoming particles down to primary energies in ca. 10 GeV - 10 TeV interval, with a median energy ca. 80-90 GeV. This measurement capability is called "scaler"
mode, since the corresponding data consist of scaler counted cascade particles with
deposited energy between 15 and 100 MeV, at the average rate of 2 kHz per individual
surface detector.
For the purpose of this master thesis I compared the data from scaler mode measurements
with measurements of neutron monitors, which are commonly used for space weather
observations. With the correlation received from the comparison, I showed that scaler
mode operation of Pierre Auger observatory can be used to monitor space weather events
such as solar cycle and the decreases in the observed galactic cosmic ray intensity due
to solar wind (Forbush decrease).
Izraz vesoljsko vreme se uporablja za spremenljive pogoje v medplanetarnem prostoru v bližini Zemlje, ki vplivajo na Zemeljsko magnetosfero, ionosfero in eksosfero.
Eden izmed glavnih vzrokov za vesoljsko vreme je sončev veter, tok nabitih delcev
(elektronov in protonov) z energijami okoli 1 keV, ki lahko povzroca geomagnetne nevihte
(perturbacije v Zemeljski magnetosferi) in polarni sij. Vpliva tudi na druge kozmicne
delce z višjimi energijami, ki vpadajo v Zemeljsko atmosfero.
Pri sipanju visokoenergijskih kozmicnih delcev na atomskih jedrih atmosferskih plinov
pride do nastanka plazov sekundarnih delcev, ki jih je mogoce zaznati preko detekcije
fluorescence ali pojava Cerenkova v atmosferi, bodisi z meritvami nabitih delcev, ki
dosežejo površje. Najvecji observatorij na svetu za meritve lastnosti kozmicnih žarkov
je observatorij Pierre Auger v Argentini, ki pokriva površino 3000 km2. Kot talne
detektorje za meritve sekundarnih delcev, ki dosežejo površje, observatorij uporablja
mrežo 1660 vodnih detektorjev cerenkova, hkrati pa uporablja tudi 27 fluorescencnih
teleskopov za meritve lastnosti plazov v atmosferi. Smeri in energije kozmicnih delcev
z energijami nad 1017 eV je mogoce rekonstruirati iz koincidence signalov iz vec talnih
detektorjev. Observatorij omogoca tudi meritev fluksa primarnih kozmicnih delcev z
nižjimi energijami (med 10 GeV in 10 TeV) v t. i. “scaler” nacinu, kjer neodvisno
merimo število vpadlih kozmicnih delcev v vsakem posameznem talnem detektorju. Pri
scaler nacinu so prešteti vsi iz kaskad, katerih energijska sled v detektorju, ni nižja
od 15MeV in ne presega 100 MeV. Povprecna frekvenca sledi na detektor je približno
2 kHz.
Podatke, pridobljene v scaler nacinu meritev sem primerjal s podatki, pridobljenimi z
nevtronskimi opazovalnicami, ki se jih uporablja za opazovanje vesoljskega vremena. S
korelacijo, dobljeno pri primerjavi, sem pokazal, da je z nizkoenergijskim nacinom delovanja
observatorija Pierre Auger ravno tako mogoce spremljati dolgorocne spremembe
vesoljskega vremena, kot je soncev cikel in zmanjšanje števila visokoenergijskih delcev,
ki dosežejo Zemljo zaradi soncnih vetrov (Forbushev pojav).
Pierre Auger Observatory
cosmic rays
space weather
Forbush decrease
observatorij Pierre Auger
kozmicni delci
vesoljsko vreme
Forbush decrease
true
true
false
Angleški jezik
Slovenski jezik
Magistrsko delo/naloga
2019-09-16 11:18:52
2019-09-17 04:27:19
2023-06-09 14:39:04
0000-00-00 00:00:00
2019
0
Nova Gorica
0
0000-00-00
NiDoloceno
NiDoloceno
NiDoloceno
0000-00-00
0000-00-00
0000-00-00
5451515
URN:SI:UNG:REP:ISZ1KGBP
Miha_Zivec.pdf
Miha_Zivec.pdf
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https://repozitorij.ung.si/Dokument.php?lang=slv&id=18664
Fakulteta za naravoslovje
0
0
0