Surface Wave Propagation
Preliminary work developing a method for surface wave detection
Amy Zheng
Andrew Johnanneson
Ultrahigh Energy Neutrino Detection
• Particles with velocity >v phase will
emit radiation due to the
Askaryan effect
• Detection is difficult due to
internally reflected waves dying
off quickly
[1]
[2]
Surface Waves as an Detection Tool
• Radiation from Askaryan cascade is trapped in Airdielectric layer between ice and firn
• In tandem with existing experiments RICE and
ANITA
[2]
[3]
[4]
Why Use Surface Waves?
• Surface waves travel between two mediums
1
▫ Amplitudes fall at the rate
r
▫ Attenuation length 2
2 times > bulk waves
[5]
• ~800 times more efficient than bulk waves
• If detection is viable, expanding existing
experiments would be far less expensive
• Surface waves may carry information about
neutrinos and their interactions with ice better
than the current method
Procedure
• 1 sending + 2
receiving antennas
displayed
waveshape
• Physically moved
antennas to
determine
wavelength and
thus index of
refraction
Example Antenna Placements
• “Surface”
• “Air”
• “In”
Translating to refractive index
n
c
v phase
c

f
(1)
Definition of Refractive Index
 Bn  
n  1   2

  Cn 
2
(2)
Sellmeier Equation
Refractive Index of Air
Single or Half λ
1.2
λ (cm)
1
0.8
0.6
0.4
0.2
0
1000 MHz
1500 MHz
Calculated (2) 1000MHz & 1500MHz n=1.000273[6]
λ (cm)
Refractive Index of Water (rms)
Single or Half λ
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
750 MHz
1000 MHz
1500 MHz
Surface
Surface
Surface
Surface
Surface In Surface Half Surface Half
Surface Half
In
Half
In
Calculated (2) n~1.3333[7]
Refractive Index of NaCl (rms)
Single or Half λ
1.8
1.6
1.4
λ (cm)
1.2
1
1000 MHz
1500 MHz
0.8
0.6
0.4
0.2
0
Surface Surface
Surface
In Surface In
In Air In
Calculated (2) n~1.544[8]
Refractive Index of Granulated Fused Silica (sand)
λ (cm)
Single or Half λ
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
1000 MHz
1500 MHz
Surface Surface
Surface
In Surface In
In Air In
Calculated (2)1000MHz n= 1.73251 [9]
Calculated (2) 1500MHz n= 1.73317
Refractive Index of Granulated Fused Silica (sand)
Multiple λ
1.4
1.2
λ (cm)
1
0.8
1000 MHz
1500 MHz
0.6
0.4
0.2
0
Surface Surface
Surface
In Surface In
In Air In
Calculated (2) 1000MHz n= 1.73251 [9]
Calculated (2) 1500MHz n= 1.73317
Measurement Complications
• Mechanical water waves appeared to alter EM
waveform
• Imprecise measurements due to hand & eye
observation
• Sand and water tend to collect in the connectors
• Angular error from planar disparity
• Waveforms disappeared & reappeared on and off
• Waveforms constantly shift amplitude
• Background EM noise & reflections often interfered
Future Steps
• Experiment using ice as a medium
• Change antenna size; more precision
• Change experimental scale
References
• [1] G.A. Askaryan, Sov. Phys. JETP 14, 441 (1961)
• [2]J.P. Ralston, Phys. Rev. D 71, 011503 (2005)
• [3] RICE Collaboration, I. Kravchenko et al., Astropart. Phys. 19, 15 (2003); S. Razzaque,
Sseunarine, D.Z. Besson, D.W. McKay, J.P. Ralston, and D. Seckel, Phys. Rev. D 65, 103002
(2002); Phys. Rev. D 69, 047101 (2004).
• [4] For information on ANITA, see http://www.phys.hawaii.edu/anita/.
• [5] J. P. Ralston “An Experiment to Detect Surface Waves on Polar Ice” (2005)
• [6] Philip E. Ciddor. Refractive index of air: new equations for the visible and near infrared,
Appl. Optics 35, 1566-1573 (1996) doi:10.1364/AO.35.001566
• [7]P. Schiebener, J. Straub, J.M.H. Levelt Sengers and J.S. Gallagher, J. Phys. Chem. Ref.
Data 19, 677, (1990)
• [8] Faughn, Jerry S., Raymond A. Serway. College Physics, 6th Edition. Toronto:
Brooks/Cole, 2003: 692.
• [9] I. H. Malitson. Interspecimen Comparison of the Refractive Index of Fused Silica, J. Opt.
Soc. Am. 55, 1205-1208 (1965) doi:10.1364/JOSA.55.001205
• [misc] Colloquium Notes from John P. Ralston
• Refractive index calculations for relative reference only:
▫
▫
▫
n found for granulated fused silica was found using Sellmeier constants for solid fused silica;
granulation affects density.
Calculated n for water is for λ of 589.29 nm
Calculated n for NaCl is for λ of 589 nm
Acknowledgements
• Dave Besson
• Marie Piasecki
• Carolyn Bandle