Design of a Transverse Field Magneto-Optical
Filter
Consortium for Undergraduate Research Experience (CURE)
Rossen Chemelekov, Los Angeles City College
Kelvin Konevsky, Los Angeles Valley College
Mentor: Dr. Neil Murphy, Jet Propulsion Laboratory
Introduction
Objective: Development and testing of a transverse field Magneto-Optical Filter
(MOF) to improve the Compact Doppler/Magnetograph (CDM)
Benefits: The CDM is smaller and lighter than current Doppler and
Magnetoraph instruments that are used in space. The transverse field MOF
should provide an improvement in the sensitivity of the CDM.
What Does a Doppler/Magnetograph Do?
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The Compact Doppler/Magnetograph is designed
to be a low-cost flight instrument that images the
full solar disk through two narrow-band filters at
the red and blue wings of the solar potassium
absorption line.
It measures the line-of-sigh velocity and magnetic
field of the Sun's photosphere.
Why study the sun?


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The Sun is a star: studying it
helps us learn about other
stars
Space Weather affects us
It's a Physical Laboratory –
fusion
The CDM is used to perform
seismology of the Sun –
sounding its interior to
determine its structure.
Magnetic field measurements
show us how active magnetic
regions and sunsports evolve
Data Collection

We use a Heliostat to track the sun and provide light to the Compact
Doppler/Magnetograph.
The Compact Doppler/Magnetograph (CDM)
The Compact Doppler/Magnetograph (CDM)
Compact Doppler/Magnetograph Overview
The CDM has three
parts:

Polarization analyzer

Filter Section
Zeeman Effect

Birefringence
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Wing Selector

Fig.1 (above) shows a schematic diagram of the Magneto-Optical Filter
Inverse Zeeman Effect
MOF pass-bands
Zeeman split
line positions
Zeeman split
line positions
Pass-bands after filter
section
Single pass-band after wing
selector
In the transverse field case,
the final pass-band is
narrower, allowing better
velocity sensitivity (less
smoothing of the solar line)
Longitudinal field case
Transverse field at 45° case
Existing Magnet Assembly
New Magnet
Designing the Transverse Field MOF
The New MOF
It Works!
Initial Sensitivity Measurements
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Fig. 3 Shows initial sensitivity measurements of the transverse field MOF based on data
collected over several days of testing.
Future Measurements
In the future further testing should be performed
with direct comparison between the sensitivity of
the two MOF.
There's a light leak-through, probably due to
contamination on the cell windows, which needs
to be addressed in order to increase the
intensity and sensitivity of the image.
Acknowledgment
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We would like to thank our mentor Dr. Neil Murphy, CURE
program director Paul McCudden, as well as Rich Alvidrez,
Marshal Fong, Dr. Milan Mijic and last but not least our
fellow interns Tzitlaly Barajas and Karen Garcia.
This research was supported by the National Science
Foundation under grant 0852088 to Cal State LA, it was
carried out at NASA's Jet Propulsion Laboratory.
Questions?
Video (above) shows a time-lapse clip of the Sun as observed on July 11th, 2012