Benjamin Culpepper

December 16, 2013

Space Plasma Physics

Purpose:

• To present the basics of magnetic storm and substorm physics while providing real-world representations of the subject matter.

• Will present example graphs of magnetic storms and substorms while providing a background for those uneducated - or for those a bit rusty - in the science.

• Will present data collected from satellites along with the appropriate analysis.

Outline:

1) Magnetic Storm Basics

2) Substorm Basics

3) Examples of Magnetic Storms

• Analysis Incorporated

4) Examples of Substorms

• Analysis Incorporated Earth's magnetic field using computer generated field

lines.

Magnetic Storm BasicsRing Current: 1) Is an electric current carried by charged particles in a planet's magnetosphere.

2) Is caused by the longitudinal drift of energetic particles (10-200 keV).

3) Is  responsible for shielding the lower latitudes of the Earth from magnetospheric electric fields.

4) System consists of a band (from 3 to 5 Earth Radii) in the equatorial plane, circulating clockwise as viewed from Earth's North.

5) Its energy is mainly carried about by the ions.

6) Its strength increases and decreases accordingly with the activity in the magnetotail region.

7) The current density caused by ring current particles with a particular energy (W) can be expressed as,

jd = 3L2nW Be Re

8) Each ring current particle drifting around the Earth forms a minute ring current. Each of those tiny, induced magnetic fields are negligible (in single particle cases); however, the magnetic disturbance due to the total current is noticeable on Earth's surface and can not be overlooked.

9) The total energy of all ring current electrons and ions at a particular radial distance is provided by, UL = ʃ nWdV

10) We may examine the magnetic field disturbance by using Biot-Savart's law and a circular loop centered at the Earth's center.

Ring Current Examples:

Consists of L-shell and electron density values used in calculating current density. [3]

High energy neutral atom image collected at a certain time. [3]

Ring Current Examples continued:

Collection of High Energy Neutral Atoms over a specific length of time (several hours or several days).This should be viewed vertically, but it was altered so visibility of the entire graph could be possible. [3]

Extreme Ultraviolet (EUV) Image.These EUV photons are resonantly scattered by singly ionized helium in the plasmasphere. [3]

Energetic neutral atom (ENA) emissions from the Earth's ring current. [1]

Magnetic Storm Basics:

1) Are a world-wide phenomenon.

2) Magnetic disturbances on the ground are smaller than that of Magnetic Substorms. However, the electrical currents that produce the disturbances can be much stronger.

3) They are a few Earth radii away from the ground and occur in the Ring Current.

4) Occur when an influx of particles are injected from the tail into the ring current. This creates an enhanced duskward electric field, causing a depression in the surface magnetic field, which can be observed on near-equatorial magnetograms.

5) Storms take place once or twice a month as opposed to substorms, which are very frequent.

UR -1BERE3 Dst

Magnetic Substorm Basics:

1) Were discovered much later than Magnetic Storms due to their ease of observation from the ground at auroral zones.

2) Substorm strength can be measured by examining particle densities in space. Due to an influx of particles there will me a measurable change in the Earth's magnetic field, giving further rise to a substorm occurring.

3) Magnetospheric substorms occur in stages: growth, onset and expansion, and recovery. The stages may be completed in a matter of a few hours.

4) The recovery of one substorm may coincide with the growth phase of another substorm. Hence, substorms occur in a time frame of hours while storms take weeks and months.

Image captured by NASA's Polar satellite. This is an auroral substorm over northern Asia. [6]

Data of Storms and Substorms:Magnetic Storms

Low-Energy Particles detected through GEOTAIL satellite for analysis of the

solar wind. [8]

Substorms:

Northward and Southward poles with aurora detected

at a specific time. [3]

Magnetic field for one day. [9]

Magnetic field for a span of days. [9] Electric field for a 24-hour

period. [9]

Hydrogen and Oxygen number densities. [9]

Ion and Electron energy flux. [9]

Ultraviolet image of a polar region. [9]

Another ultraviolet image from POLAR. [9]

POLAR's visible imaging system.

A clearer, mapped region of Earth using POLAR's

ultraviolet image.

Acknowledgments:

[1] "Earth: Ring Current." Cosmos Portal. Digital Universe, November 25, 2007. Web. December 1, 2013.

[2] Baumjohann, Wolfgang. Treumann, Rudolf A. Basic Space Plasma Physics. London: Imperial College Press, 1997. Pages 43-45. Print.

[3] Mitchell, Don at APL. Reinisch, B. W. at UMLCAR. Sandel, Bill at University of Arizona. Mends, S. at UC Berkely and SSL. CDAWeb.

[4] "EUV Imaging: Introduction." Image. Web. December 1, 2013.

[5] "Earth: Ring Current." Cosmos Portal. Digital Universe, November 25, 2007. Web. Image. December 1, 2013.

[6] "Polar Substorm." Science News. National Aeronautics and Space Administration, March 2, 2000. Web. December 1, 2013.

[7] " Substorms." Stern, David P. Peredo, Mauricio. National Aeronautics and Space Administration, 25 November 2001. Web. Decebmber 1, 2013.

[8] Frank, L. at University of Iowa. Mukal, T. at ISAS. McComas, D.J. at SWRI. Szabo, A. at NASA/CSFC. Nese, N. at Bartol Research Institute. CDAWeb.

[9] Russell, C. T. at UCLA. Mozer at UC Berkely. Scudder, J. at University of Iowa. Peterson, W. K. at LASP. Parka, G. at University of Washington. Frank, A. at University of Iowa. CDAWeb.