Surface Wave Propagation

Preliminary work developing a method for surface wave detection

Amy ZhengAndrew Johnanneson

Ultrahigh Energy Neutrino Detection•Particles with velocity >

will emit radiation due to the Askaryan effect [1]

•Detection is difficult due to internally reflected waves dying off quickly[2]

phasev

Surface Waves as an Detection Tool

•Radiation from Askaryan cascade is trapped in Air-dielectric layer between ice and firn [2]

•In tandem with existing experiments RICE [3]

and ANITA [4]

Why Use Surface Waves?

•Surface waves travel between two mediums[5]

▫Amplitudes fall at the rate ▫Attenuation length times > bulk

waves•~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

r

1

22

Procedure

•1 sending + 2 receiving antennas displayed waveshape

•Physically moved antennas to determine wavelength and thus index of refraction

Example Antenna Placements

•“Surface”

•“In”

•“Air”

Translating to refractive index

fc

v

cn

phase

n

n

C

Bn

2

2

1

(1)

(2)

Definition of Refractive Index

Sellmeier Equation

Refractive Index of Air

T1 T2 T3 T4

Avera

ge

Calcu

late

d Ave

rage

Adjus

ted

Calcu

late

d Ave

rage rm

s0

0.4

0.8

1.2

1000 MHz1500 MHz

Calculated (2) 1000MHz & 1500MHz n=1.000273[6]

Single or Half λ

λ (

cm)

Refractive Index of Water (rms)

Surface Surface Surface

Surface Surface

Half

Surface In In

Surface Half Half

Surface Half In

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

750 MHz1000 MHz1500 MHz

Calculated (2) n~1.3333[7]

Single or Half λ

λ (

cm)

Refractive Index of NaCl (rms)

Surface Surface Surface

In Surface In In Air In0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

1000 MHz1500 MHz

Single or Half λ

λ (

cm)

Calculated (2) n~1.544[8]

Refractive Index of Granulated Fused Silica (sand)

Surface Surface Surface

In Surface In In Air In0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

1000 MHz1500 MHz

Calculated (2)1000MHz n= 1.73251 [9]Calculated (2) 1500MHz n= 1.73317

Single or Half λ

λ (

cm)

Refractive Index of Granulated Fused Silica (sand)

Surface Surface Surface

In Surface In In Air In0

0.2

0.4

0.6

0.8

1

1.2

1.4

1000 MHz1500 MHz

Calculated (2) 1000MHz n= 1.73251 [9]Calculated (2) 1500MHz n= 1.73317

Multiple λ

λ (

cm)

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

Any Questions?