A Case Study of Energy Deposition and Absorption by Magnetic Cloud Electrons and Protons over the High Latitude Stations: Effects on the Mesosphere and Lower Thermosphere

Abstract

Several possible characteristics of magnetic clouds (MCs) have been discussed in the literature, but none appears to explain all the effects from accumulated observations. MC characteristics range from low proton temperature and plasma beta, to high magnetic field magnitude, to smooth rotation in the direction of the magnetic field thus resulting in strong geomagnetic disturbances. Varied instrumentation which is located not only in SANAE IV, Antarctica, but also at Halley, a same radial distance (L ~ 4) in the southern hemisphere and in the vicinity of a conjugate location in northern hemisphere provide an opportunity to test theories applied to high latitude heating rates on the arrival of MC. The Halley riometer is used to monitor coincidences of absorption with the arrival of MC which was observed on 8 November 2004. Using the Monte Carlo Energy Transport Model (MCETM), the corresponding altitude of electron and proton energy distribution indicates the importance of MC triggered geomagnetic storms on mesosphere dynamics.Key words: Magnetic Cloud, Precipitation, MLT region, Absorption, Energy deposition, L shell Citation: Ogunjobi, O., V. Sivakumar, and N. Mbatha, 2014: A case study of energy deposition and absorption by magnetic cloud electrons and protons over the high latitude stations: Effects on the mesosphere and lower thermosphere. Terr. Atmos. Ocean. Sci., 25,[219][220][221][222][223][224][225][226][227][228][229][230][231][232]

A superposed epoch study of the effects of solar wind stream interface events on the upper mesospheric and lower thermospheric temperature

“…Ozone itself is significant in the absorption of solar ultraviolet radiation and thus may affect the radiative balance, temperature and dynamics of the atmosphere. While our observations of the cooling effect below 95 km is similar to Pancheva et al (2007), it is however not fully consistent with the work of von Savigny et al (2007) A heating effect was also found below 100 km in the Southern hemisphere in a recent case study by Ogunjobi et al (2014) for a different type of storm-driven event known as magnetic cloud (MC). The apparent contradictory temperature responses demonstrate the complexity of the energy budget in the MLT region.…”

“…The riometers are mostly widebeam, typically 30 MHz, and sensitive to any incident particle population capable of reaching the altitude range of 70-100 km. In order to identify extraordinary ionospheric absorption from remote measurements, a reference Quiet Day Curve (QDC) value is an important parameter to be considered (Ogunjobi et al, 2014). Any deviations from this expected value must then be due to absorption in the ionosphere.…”

“…We consider the energy deposition height profile using the Monte Carlo Energy Transport model (MCTEM, Ogunjobi et al, 2014). Fig.…”

A comparison of outer electron radiation belt dropouts during solar wind stream interface and magnetic cloud driven storms

“…In other words, OMNI database consists of geomagnetic storms that were identified from the measurement of the global variation in the Earth's magnetic field at the Earth's bow shock nose. The dataset is created at National Space Science Data Center (NSSDC) by interspersing, after cross-normalizing, field and plasma data from each of several spacecrafts that contribute into the measurements (King and Papitashvili 2005;Ogunjobi et al 2014a). From different parameters available at OMNI, only those that are relevant to characterizing the SI and MC were extracted as presented in section 3.…”

Evidence of Polar Mesosphere Summer Echoes Observed by SuperDARN SANAE HF Radar in Antarctica

“…On the other hand the visible aurora is an effect of precipitating energetic particles interacting with the Earth's magnetic field. The interactions can create steep electron density gradients and by extension cause cosmic radio noise at the mesopause region (e.g., Wu et al 2013;Ogunjobi et al 2014a). The riometer data may permit us to, indirectly, examine the possible dependence of SuperDARN-PMSE on ionospheric echoes produced by energetic particle precipitation.…”