Using solar wind proton temperature measurements from WIND to determine the probability of the duration above a specified temperature threshold

Abstract:
Hourly averaged proton temperature, density, and velocity measurements from WIND have been adequately modeled by the normal probability density for the logarithm of these quantities, by Burlaga et. al. Magnetic Field Strength (Burlaga) and AE Index (Watkins) can be similarly modeled. We have revisited the proton temperature measurements from WIND during 1997 and determined the Autocorrelation function (ACF). The ACF is used to determine the probability of duration above a (user specified) threshold temperature. Historic temperature time series for 1997 and later is used to assess the predictions using the ACF and first passage time theory. This method will be applied to proton and (four second ) electron temperature measurements from Cluster taken in the solar wind. These methods can be extended to density, velocity, magnetic field strength, AE, etc.

Plasma sheet energetic electrons: their relationship with the solar wind and geosynchronous electrons, and preliminary case studies of plasma sheet
electron dropouts

Toward quantitative understanding of space storm energetics

Abstract:
Determining how much energy is transported into the magnetosphere during different types of activity and how it is distributed and used in the system are difficult questions to answer with direct observations. I will review how we have been attacking this problem on several frontiers in Helsinki. We started the work about 10 years ago in a classical way using various proxies to determine the energy output in the ionosphere and inner magnetosphere and comparing the results with empirical energy coupling functions based on solar wind data. The next step was to employ the global magnetosphere-ionosphere MHD-based simulation tool at FMI, GUMICS-4, for quantitative studies of the energy transfer and comparisons with actual substorm and storm events. Recently we invested a significant effort in studies of energy conversion using of Poynting vector divergence calculations based on simulation output. In the near future we will attempt to use Cluster observations on the magnetopause to benchmark our simulation results on energy transfer. This is a part of a new 5-year project QuESpace (Quantifying Energy Circulation in Space Plasma; PI Minna Palmroth) supported by the newly-established European Research Council. Within this project we will be able to invest more resources to further development and applications of our present magnetosphere-ionosphere simulation package and begin developing own Vlasov simulations for magnetospheric investigations.

Hybrid code simulations of the solar wind interaction with Pluto

Abstract:

Pluto's low gravity implies that the atmosphere is only weakly bound and significant hydrodynamic outflow can exist. Though surface spectroscopy of Pluto has revealed methane frost, the dominant escaping neutral gas is thought to be N_2. These escaping neutrals are photoionized and the heavy ions (N_2^+) move away from Pluto in the direction perpendicular to the solar wind flow (i.e. nearly unmagnetized relative to the length scales of the plasma interaction region). The turning distance of the solarwind protons at the magnetic pileup boundary is large compared to the interaction region. As a result, large ion gyroradius affects determine Pluto's highly asymmetric interaction with the solar wind. We use a three-dimensional hybrid code (fluid electrons, kinetic ions) to investigate the geometry of the interaction region for a variety of possible atmospheric escape rates in anticipation of the New Horizons encounter with Pluto. We find considerable structuring in the wake region due to bi-ion waves and Kelvin-Helmholtz waves. The shock structures vary from a simple Mach cone for low escape rates (~2x10^26 s^-1) to a full detached bow shock for large escape rates (~2x10^28 s^-1).

Global energy partition during the 21-22 January 2005 geomagnetic storm: Ring current energization

Jupiter-related talk entitled, "Acceleration processes above the Io foot print"

Complexities of a 3-D plasmoid flux rope as shown by an MHD simulation

(Nathan's paper on this subject was recently accepted for publication in JGR, where it is now in press.)

Electron phase space holes during magnetic reconnection