Extreme changes in the dayside ionosphere during a Carrington-type magnetic storm

J. Space Weather Space Clim. 2 (2012) A05 DOI: 10.1051/swsc/2012004  Owned by the authors, Published by EDP Sciences 2012 Extreme changes in the dayside ionosphere during a Carrington-type magnetic storm Bruce T. Tsurutani1,*, Olga P. Verkhoglyadova1,2, Anthony J. Mannucci1, Gurbax S. Lakhina3, and Joseph D. Huba4 1 Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA *corresponding author: e-mail: 2 CSPAR, University of Alabama, Huntsville, Alabama, USA 3 Indian Institute of Geomagnetism, Navi Mumbai, Maharastra, India 4 Naval Research Laboratory, Washington DC, USA Received 9 February 2012 / Accepted 12 May 2012 ABSTRACT It is shown that during the 30 October 2003 superstorm, dayside O+ ions were uplifted to DMSP altitudes (~850 km). Peak densities were ~9 · 105 cm 3 during the magnetic storm main phase (peak Dst = 390 nT). By comparison the 1–2 September 1859 Carrington magnetic storm (peak Dst estimated at 1760 nT) was considerably stronger. We investigate the impact of this storm on the low- to mid-latitude ionosphere using a modified version of the NRL SAMI2 ionospheric code. It is found that the equatorial region (LAT = 0 ± 15) is swept free of plasma within 15 min (or less) of storm onset. The plasma is swept to higher altitudes and higher latitudes due to E · B convection associated with the prompt penetration electric field. Equatorial Ionization Anomaly (EIA) O+ density enhancements are found to be located within the broad range of latitudes ~ ± (25–40) at ~500–900 km altitudes. Densities within these peaks are ~6 · 106 oxygen ions-cm 3 at ~700 km altitude, approximately +600% quiet time values. The oxygen ions at the top portions (850–1000 km) of uplifted EIAs will cause strong low-altitude satellite drag. Calculations are currently being performed on possible uplift of oxygen neutrals by ion-neutral coupling to understand if there might be further significant satellite drag forces present. Key words. ionosphere (equatorial) – ionosphere (mid latitude) – electric field – coronal mass ejection (CME) – flares 1. Introduction Obayashi (1967), Nishida (1968), and Kelley et al. (1979, 2003) have reported strong ionospheric effects associated with magnetospheric substorms. These effects are explained by the appearance of dawn-to-dusk electric fields in the dayside near-equatorial ionosphere which has received the name ‘‘prompt penetrating electric fields’’ or PPEFs. More recently, such strong ionospheric effects have been noted during magnetic storms (Sobral et al. 1997, 2001; Sastri et al. 2002; Tsurutani et al. 2004, 2008a, 2008b; Huang et al. 2005; Mannucci et al. 2005, 2008; Koga et al. 2011; Siqueira et al. 2011). The importance of the latter is that during storms, the electric fields are more intense (Tsurutani et al. 2004) and have longer durations up to hours (Huang et al. 2005). The ionospheric effects during storms would thus be expected to be stronger and more prominent. These PPEFs may be one and the same as the magnetospheric convection electric fields that drive the nightside plasmasheet into the inner magnetosphere, creating the ring current during magnetic storms (Tsurutani et al. 2004). For the interested reader, intense magnetic storms have been discussed in Tsurutani et al. (1988, 1992, 2008a), Gonzalez et al. (1994, 2011), and Echer et al. (2008a, 2008b). For a more detailed discussion of the relationship between PPEFs and magnetic storms, we refer the reader to Tsurutani et al. (2008b). The cause for an increase in the total electron content (TEC) during magnetic storm main phases has been explained in Tsurutani et al. (2004). During a magnetic storm when the PPEF reaches the equatorial dayside ionosphere, the E · B convection uplifts ionospheric plasma to greater heights and (absolute) magnetic latitudes. At these greater heights, the recombination time scale is considerably longer than at lower altitudes. Solar photoionization creates new electron-ion pairs at the lower heights, replenishing the displaced plasma. Thus, the overall TEC of the ionosphere increases. This process has been called the ‘‘dayside ionospheric superfountain’’ (Mannucci et al. 2005; Tsurutani et al. 2008b) and is one type of a ‘‘positive ionospheric storm’’ (Prölss 1993). Although the 30–31 October 2003 storm was intense (peak Dst = 390 nT), the 1–2 September 1859 Carrington event was far more intense. Tsurutani et al. (2003) and Lakhina et al. (2012) used the Colaba, India magnetometer data, the Carrington solar flare and magnetic storm timing and other ancillary information to determine the Dst of the event to be ~ –1760 nT, over four times the intensity of the October 2003 storm and more than three times the intensity of the 13 March 1989 Quebec, Canada storm. The latter storm knocked out the Hydro-Quebec power grid for ~9 h. Because of this great intensity, the Carrington storm (the authors pay tribute to R. Carrington by naming it after him) had related effects that influenced humankind. At the time, telegraph communication was the ‘‘high technology’’ of the era. The magnetic storm induced currents in the east-west lying telegraph lines such that arcing caused fires at telegraph stations in both the United States and Europe (Loomis 1861). It is realized that if such an intense storm occurred today, similar induced This is an Open Access article distributed under the terms of creative Commons Attribution-Noncommercial License 3.0 J. Space Weather Space Clim. 2 (2012) A05 currents would occur in our power (and other) lines (Bolduc 2002). NASA, the Department of Defense, and Homeland Security are investigating the possibility of major power grid failures if such a magnetic storm occurred today. Are there other problems that can occur in our high-tech society due to the occurrence of such storms? The purpose of this paper is to study the gross properties of the ionosphere during a Carrington-type storm. 2. Methods of analyses We will explore the dayside ionospheric perturbations using the SAMI2 code (Huba et al. 2000, 2002). SAMI2 is a low-latitude ionospheric model which describes dynamics and chemical evolution of seven ion species and seven corresponding neutral species. The code solves collisional two-fluid equations for electrons and ions along the Earth’s dipole magnetic field lines, taking into account photoionization of neutrals, recombination of ions and electrons, and chemical reactions. The code was modified to allow an electric field input (Verkhoglyadova et al. 2007) and more recently (for this paper) has been further modified to insert 3-h Ap indices instead of daily values. The SAMI2 code calculates ionospheric plasma transport in a direction perpendicular to the ambient magnetic field lines. Diurnal variations are associated with a variable electric field, which we have assumed has a sinusoidal shape in the form sin[(t 7)/24] where t is the time in local time hours. We take a peak field of 0.53 mV m 1 electric field in (...truncated)