Magnetic field reversal

The graph shows a comparison of the observed magnetic profile for the seafloor across the East Pacific Rise against a profile calculated from the Earth's known magnetic reversals, assuming a constant rate of spreading. Credit: W. Jacquelyne Kious and Robert I. Tilling, USGS.

This laboratory is an activity for you to describe a magnetic field reversal.

Some suggested reversal entities to consider are electromagnetic radiation, neutrinos, mass, time, Euclidean space, Non-Euclidean space, a dynamo, and spacetime.

More importantly, there are your magnetic field reversal entities.

You may choose to define your entities or use those already available.

Usually, research follows someone else's ideas of how to do something. But, in this laboratory you can create these too.

Evaluation

evaluation activity

Okay, this is an astronomy magnetic field reversal laboratory, but you may create what a magnetic field reversal is.

Yes, this laboratory is structured.

I will provide one example of techniques to cause a magnetic field reversal. The rest is up to you.

Questions, if any, are best placed on the discussion page.

Notations

You are free to create your own notation, or use those already presented.

Control group

For creating a magnetic field reversal technique, what would make an acceptable control group? Think about a control group to compare your magnetic field reversal technique or your process of creating a magnetic field reversal to.

Sampling

Searching SAO/NASA Astrophysics Data System (ADS) with "Earth's magnetic reversals" yields 43 abstracts. Here is a sampling of likely causes:

  1. 1985:Any "field reversal [may be] linked to biological extinction7–12 [...] the reversal record of the past 165 Myr [shows that a] stationary periodicity of 30 Myr emerges (superimposed on the non-stationarities already established by others5), which predicts pulses of increased reversal activity centred at 10, 40, 70,… Myr BP."[1] See hypotheses 2 and 3. So what's causing the 30 Myr period?
  2. 1986:A "recently observed 15 Myr periodicity is probably a harmonic of the 29.5-30.5 Myr period. The calculations do not confirm an inherent magnetic reversal property of the earth. The reversals may arise from tectonic events or from impacts from extraterrestrial objects."[2] Here, can be external events or tectonic events for the origin of reversals.
  3. 1994:"The precession peaks found in the δ18O record from core MD900963 are in excellent agreement with climatic oscillations predicted by the astronomical theory of climate."[3] In other words, orbital changes have produced or induced magnetic field reversals.
  4. 1994:"The Earth's geomagnetic field reverses its polarity at irregular time intervals. {It] is not clear whether a reversal is a deterministic (low dimensional) or a random (high-dimensional) process; the duration-frequency distribution of the polarity time intervals resembles those generated by random processes, but many models suggest that a geomagnetic field reversal can be the outcome of a deterministic dynamics, that of the convection in the Earth's outer core. [The] limited size of the magnetic reversal data (282 points) and the poor convergence of the correlation integrals make a quantitative assessment of low-dimensional chaos impossible."[4]
  5. 2000:"Earth's magnetic field is generated by fluid motion in the liquid iron core. Details of how this occurs are now emerging from numerical simulations that achieve a self-sustaining magnetic field. Early results predict a dominant dipole field outside the core, and some models even reproduce magnetic reversals."[5] Here, the geodynamo is the source of the reversals.
  6. 2003: The "redistribution of magnetic polarities in the inner heliosphere during [a 10.5-month period of maximum solar activity] can be simply described by a gradual 180 degree rotation of the dipole axis from near-alignment with one solar rotational pole to the other."[6]
  7. 2013:"Regeneration of the Earth's magnetic field by convection in the liquid core produces a broad spectrum of time variation. [...] the amplitude of convective fluctuations in the core [is predictable], and establish a physical connection to the rates of magnetic reversals and excursions."[7]

Report

Title

by line

Abstract

Introduction

Experiment

Results

Discussion

Conclusion'

Evaluation

To assess your magnetic field reversal method, including your justification, analysis and discussion, I will provide such an assessment of my example for comparison.

Evaluation

Research

Hypotheses:

  1. Magnetic field reversals affect the local magnetic fields within crystallizing liquids.
  2. Magnetic field reversals may cause the ionosphere to contact the surface of the Earth during the reversal period.
  3. Magnetic field reversals may allow increased radiation to irradiate the upper crustal rocks to significant depths during the reversal period.
  4. Subject to the origin of magnetic field reversals, they may cause significant increases in volcanic activity during the reversal period.
  5. Magnetic field reversals of the Sun occur with the sunspot cycle which may have its origins in enhanced electron current from Jupiter and Venus when perihelion is coincident.

Control groups

This is an image of a Lewis rat. Credit: Charles River Laboratories.

The findings demonstrate a statistically systematic change from the status quo or the control group.

“In the design of experiments, treatments [or special properties or characteristics] are applied to [or observed in] experimental units in the treatment group(s).[8] In comparative experiments, members of the complementary group, the control group, receive either no treatment or a standard treatment.[9]"[10]

Proof of concept

Def. a “short and/or incomplete realization of a certain method or idea to demonstrate its feasibility"[11] is called a proof of concept.

Def. evidence that demonstrates that a concept is possible is called proof of concept.

The proof-of-concept structure consists of

  1. background,
  2. procedures,
  3. findings, and
  4. interpretation.[12]

See also

  • Magnetic field

References

  1. ↑ David M. Raup (28 March 1985). "Magnetic reversals and mass extinctions". Nature 314 (6009): 341-3. doi:10.1038/314341a0. http://www.nature.com/nature/journal/v314/n6009/abs/314341a0.html. Retrieved 2015-06-17.
  2. ↑ Richard B. Stothers (31 July 1986). "Periodicity of the Earth's magnetic reversals". Nature 322 (6078): 444-6. doi:10.1038/322444a0. http://www.nature.com/nature/journal/v322/n6078/abs/322444a0.html. Retrieved 2015-06-17.
  3. ↑ Frank C. Bassinot, Laurent D. Labeyrie, Edith Vincent, Xavier Quidelleur, Nicholas J. Shackleton, Yves Lancelot (August 1994). "The astronomical theory of climate and the age of the Brunhes-Matuyama magnetic reversal". Earth and Planetary Science Letters 126 (1-3): 91-108. doi:10.1016/0012-821X(94)90244-5. http://www.sciencedirect.com/science/article/pii/0012821X94902445. Retrieved 2015-06-17.
  4. ↑ Massimo Cortini and Christopher C. Barton (September 1994). "Chaos in geomagnetic reversal records: A comparison between Earth's magnetic field data and model disk dynamo data". Journal of Geophysical Research 99 (B9): 18,021-33. doi:10.1029/94JB01237. http://adsabs.harvard.edu/abs/1994JGR....9918021C. Retrieved 2015-06-18.
  5. ↑ Bruce A. Buffett (16 June 2000). "Earth's Core and the Geodynamo". Science 288 (5473): 2007-12. doi:10.1126/science.288.5473.2007. http://www.sciencemag.org/content/288/5473/2007.full. Retrieved 2015-06-17.
  6. ↑ G. H. Jones and A. Balogh (6-11 April 2003). "Reversal of the solar magnetic dipole as observed at Ulysses". Nice, France: EGU. Retrieved 2015-06-19.
  7. ↑ Bruce A. Buffett, Leah Ziegler, and Cathy G. Constable (October 2013). "A stochastic model for palaeomagnetic field variations". Geophysical Journal 195 (1): 86-97. doi:10.1093/gji/ggt218. http://adsabs.harvard.edu/abs/2013GeoJI.195...86B. Retrieved 2015-06-17.
  8. ↑ Klaus Hinkelmann, Oscar Kempthorne (2008). Design and Analysis of Experiments, Volume I: Introduction to Experimental Design (2nd ed.). Wiley. ISBN 978-0-471-72756-9. http://books.google.com/?id=T3wWj2kVYZgC&printsec=frontcover.
  9. ↑ R. A. Bailey (2008). Design of comparative experiments. Cambridge University Press. ISBN 978-0-521-68357-9. http://www.cambridge.org/uk/catalogue/catalogue.asp?isbn=9780521683579.
  10. ↑ "Treatment and control groups, In: Wikipedia". San Francisco, California: Wikimedia Foundation, Inc. May 18, 2012. Retrieved 2012-05-31.
  11. ↑ "proof of concept, In: Wiktionary". San Francisco, California: Wikimedia Foundation, Inc. November 10, 2012. Retrieved 2013-01-13.
  12. ↑ Ginger Lehrman and Ian B Hogue, Sarah Palmer, Cheryl Jennings, Celsa A Spina, Ann Wiegand, Alan L Landay, Robert W Coombs, Douglas D Richman, John W Mellors, John M Coffin, Ronald J Bosch, David M Margolis (August 13, 2005). "Depletion of latent HIV-1 infection in vivo: a proof-of-concept study". Lancet 366 (9485): 549-55. doi:10.1016/S0140-6736(05)67098-5. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1894952/. Retrieved 2012-05-09.

External links

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Educational level: this is a research resource.
Subject classification: this is an astronomy resource.
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