500 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 33, NO. 2, APRIL 2005
The Aurora Borealis in Southern USAIgor Alexeff and Sriram M. Parameswaran
AbstractThis paper is an observation of the Aurora Borealis,commonly known as the northern lights in Southern USA. Thisis only the second time in a century has this rare spectacular eventoccurred in the observed location.
Index TermsAtmospheric effects, Aurora Borealis, naturalphenomena.
THE Aurora Borealis is a natural display mainly caused byhigh-energy electrons and ions originating in the Sun en-tering the earths atmosphere in narrow regions centered on themagnetic poles. These ions and electrons are directed by theearths magnetic field to high latitudes. They collide with atmo-spheric atoms which are excited to higher energy levels. Theseexcited atoms emit rapidly varying visible light in a curtain-likevolume as they return to lower energy levels thereby creatingthe aurora . Fig. 1 is a photograph of a rare occurrence of theAurora Borealis in southern USA. The unusual feature of thisaurora, is that it occurred so far south in the USA at latitude 36. The discharge lasted for more than 4 h. The local radio sta-tion had announcements of a red glow in the sky. This photo
Manuscript received June 30, 2004; revised November 8, 2004.The authors are with the University of Tennessee, Knoxville, TN 37996-2100
USA (e-mail: email@example.com; firstname.lastname@example.org).Digital Object Identifier 10.1109/TPS.2005.845046
was made about midnight on Monday, November 5, 2001 inOak Ridge, TN. The view is north from the Oak Ridge CountryClub (golf course), overlooking the Oak Ridge Turnpike, StateHighway 58 (note the string of automobile headlights) with aview of black Oak Ridge at the background. Alexeffs home isone of the illuminated spots toward the right of the picture, about
way up the hill. The photo was made with a CANON Eoscamera, an Eos f 1.8 lens, and Fujichrome film ASA 1600. Theexposure was about 4 s at F 1.8. This is only the second timein a century has this event been observed in this location. Thereis no record in hand detailing the event causing the dischargeand the source of the colors. The picture was very popular inthe newspapers, and was nationally syndicated. This picture isof much higher quality than that which appeared in the press.According to Alexeff, this is the only intense aurora that has ap-peared in this area in the past 44 years, during which he has livedin Tennessee.
 G. Baranoski, Simulating the Aurora Borealis, Depart. Computer Sci.,The University of Calgary, Calgary, Canada, Tech. Rep. 2000/655/07,Mar. 2000.
 J. M. Vaquero and M. C. Gallego, Two early observations of aurora atlow latitude, Annales Geophysicae (2001), vol. 19, pp. 809811, 2001.
0093-3813/$20.00 2005 IEEE