MuSTAnG – Muon Spaceweather Telescope for Anisotropies at Greifswald*

Poster Content

• Space Weather Physics behind Cosmic Ray Muon Anisotropy• MuSTAnG Consortium and Status of Construction• MuSTAnG in the International Muon Telescope Network

F. Jansen1,2 and R. Hippler1

1 University of Greifswald, Institut for Physics, Domstr. 10a, 17489 Greifswald, Germany2 1A - First Applications and Management Consultancy for Space Weather Service, Research, Education and Culture, Markt 15-19, PF 3119, 17461 Greifswald, Germany

jansen@physik.uni-greifswald.de and hippler@physik.uni-greifswald.de

*ESA/ESTEC contract 18835/04/NL/MV

10 hours before SSC

Space Weather Physics behind Cosmic Ray Muon Anisotropy: First Observations

Sundirection

Example: space weather storm on 9th September 1992(Figures right (from top to bottom, black line is the sudden commencement (SSC) )

1) change of Kp index versus time2) cosmic ray neutron monitor counts versus time (no hints for changing counts rate before SSC)3) pitch angle versus time, but with cosmic ray muon telescope data (Nagoya Scintillator Telescope) enhancement of comic ray muon anisotropy into Sun direction (black circles) about 10 hours before SSC4) change of interplanetary field magnitude5) change of solar wind velocity

Details see inMunakata et al. J. of Geophys. Res. 105 (A12) 27457, 2000

Space Weather Physics behind Cosmic Ray Muon Anisotropy: Physics behind the Muon Anisotropy

1) Ground-level CR detectors scan various directions in space (including to the Sun) as Earth rotates.2) Daily variations in counting rates on ground reflect anisotropic intensity distribution of cosmic rays in space.3) Semidiurnal variation due to interactions in the heliosphere of outward moving solar wind and inward diffusing galactic cosmic rays.4) Semidiurnal variations were observed by neutron monitors, ion chambers and muon telescopes.5) Detectors observe reduced flux of CR particles moving away from the shock (with small pitch angles), due to CR depleted region behind the shock.6) CR intensity deficit or increase in the order of 1 % to 4 % (PAD – Precursor Anisotropy Decrease, PAI – Precursor Anisotropy Increase).

7) First detection of the shock at a distance of r ~0.1 λP cos ß (λP scattering mean free path of cosmic rays, angle between Sun-Earth line and the mean IMF at Earth)

8) λP about 1 AU for 10 GeV CRs (neutron monitor energy range) => 5 hours before

shock wave arrival

9) Muon telescopes measure at 50 GeV => λP much longer => 24 hours before shock wave arrival !!!

Space Weather Physics behind Cosmic Ray Muon Anisotropy: Sketch of Physics

MuSTAnG Status, the Consortium*

University of Greifswald: F. Jansen, R. Hippler

1A Greifswald / Germany: F. Jansen, G. Bartling

IEPSAS Kosice / Slovakia: K. Kudela

AAD Hobart / Australia: M. Duldig, J. Humble

University of Bern / Switzerland: E. Flückiger

HTS Dresden / Germany: W. Göhler, S. Brunner

Shinshu University / Japan: K. Munakata

UAS Stralsund / Germany: G. Kolbe, B. Zehner

Hanse city of Greifswald / Germany

*ESA/ESTEC contract 18835/04/NL/MV

MuSTAnG Status: Telescope Principles

Detection / construction principle:- two layers (8 sqm) of plastic scintillators (PS) with wavelength shifter, lead layer (4 sqm) between the PS layers for low energy CR absorption- high voltage photomultiplier tubes for signal detection and direction determination due to coincidence measurements at different plastic scintillator plates- electronics and data recording

Schedule:- start of construction January 2005- current status: development and order of hardware, electronics and software- data available summer 2006

Scintillator

Optical coupling

Light amplification

Data acquisition

Incoming Muon

MuSTAnG Status: Layout

4m2 prototype: 2m x 2m,

2 detector layers: 8m2,

1 lead layer: 4m2

entire height about 2m

readout electronics:

wavelength shifter and

8 PMTs

entire weight: 3 t

MuSTAnG in the International

Muon Telescope Network MuSTAnG becomes part of the international European -Australian –

Japanese – Brazil muon telescope networkAustralia: MPC (Mawson Propotional Counter),

HST (Hobart Scintillator Telescope, 18 sqm detector size)

Japan: NST (Nagoya Scintillator Telescope, 72 sqm detector size)

Brazil: SMST (San Martinho Scintillator Telescope, 8 sqm detector size)

Part of SWENET and COST 724 data (WG2, WG4)

Mawson PC, HST, NST, SMST and MuSTAnG

MPC

SMST

HST

NST MuSTAnG

MuSTAnG in the International Muon Telescope Network: Asymptotic Viewing Directions of Network Telescopes

- a nearly full coverage (and therefore a 24 hour observation of CME - propagation) is possible,

- 20 to 24 hours forecast of CME arrival time is expected

+ 54° MuSTanG

+ 35° NST

- 29° SMST

- 43° HST

24/2

t ,t ,t ,tI

ct

tsinctcosst

tsinstcoscttIctI

GEOz

GEOy

GEOx

0

0j,li

GEOz

il

j,liil

j,liGEOy

il

j,liil

j,liGEO00

j,i0cal

j,i x

MuSTAnG in the International Muon Telescope Network: Equation for Muon Data

Abbreviations- jth telescope (for example j=1 MustAnG...), with ith detector at the different geographical locations, - t is UT, ti is the local time of the ith detector, - s and c are the „coupling coefficients“: function of primary CR spectrum, observed muon flux (cph as function of zenith and azimutal angles) including asymptotic viewing directions, telescope response function (telescope specifics)- I0(t) isotropic CR component (eg. yearly mean) and - ξx

GEO, ξyGEO, ξz

GEO anisotropy vectors in geographical coordinate system First step of solving the equationξx

GEO, ξyGEO, ξz

GEO geographical coordinate system, and than ...

The aim is to find a best-fit calculation Ii,jcal(t) for the observed CR muon density Ii,j

obs(t)

Munakata et al.,Adv.Space Research 2005, in press

MuSTAnG in the International Muon Telescope Network: Solving the Equation for Muon Data

- next steps: a) coordinate transformation from ξx

GEO, ξyGEO, ξz

GEO

to ξxGSE, ξy

GSE, ξzGSE geocentric solar ecliptic system

(ξx and ξy (ecliptic plane anisotropy vectors), ξz – north / south anisotropy vector) => result Ii,j

cal(t) in GSE system and

b) consideration of solar wind convection caused anisotropy (different solar wind speed, real time ACE s/c data) and

c) consideration of anisotropy due to Earth‘s orbital motion around the Sun (30 km/s, Compton-Getting anisotropy)

FINAL RESULT OF NUMERICAL SOLUTION

best fit anisotropy vector ξx, ξy, ξz and Ii,jobs(t) in GSE coordinate system