IMPRS Evaluation 2005

Agenda - Abstracts of Talks - List of Posters

Agenda

10 Nov	from 18:00	Meeting with Evaluation Committee and Executive Committee at Gebhards Hotel Göttingen, Restaurant Georgia-Augusta-Stuben for Dinner
11 Nov	09:00-09:45	Sami K. Solanki: Welcome and Introduction
	09:45-11:00
		Nazaret Bello González: Sunspot penumbrae: observations and numerical modelling
		Jean-Mathias Grießmeier: Exoplanetary radio emissions: a future observation method
		Ana Teresa Monteiro Tomás: Energetic particles in the Jovian magnetosphere and their relation to auroral emissions
		Monika Buske: Thermal evolution of the martian interior
		Mark Cheung: Magnetic flux emergence in the photosphere of the Sun
	11:00-12:30	Poster Session
	12:30-13:30	Lunch and Discussions
	13:30-14:30	Discussion with Students
	14:30-15:30	Discussion with Supervisors and Executive Committee
	15:30-16:30	Internal Discussion
	16:30-17:00	Summary of the Evaluation

Abstracts of Talks

Sunspot penumbrae: observations and numerical modeling

Nazaret Bello González

Institute of Astrophysics, University of Göttingen

We describe a study on spectropolarimetry of sunpot penumbrae. On the one hand, the study is focused on the analysis of 2D spectropolarimetric data observed with very high spatial resolution and, on the other hand, on the synthesis of Stokes profiles by means of numerical simulations of the penumbral atmosphere through a two-component atmopsheric model. Comparisons of the line-of-sight component velocities with the intensity maps in the whole sunspot area show that on the centre-side penumbra the Evershed flow (radial outflow of gas, Evershed 1909) is carried by bright filaments while on the limb side it is carried by dark filaments. The observations also confirm the un-combed structure of the magnetic field. To explain the picture about the penumbral fine structure seen in the observations we compare, in a first approximation, the observed Stokes profiles with synthetic ones. For the synthesis of Stokes profiles by solving the radiative transfer problem, we have considered a penumbral model with two components: a magnetic flux tube embedded in a static penumbral background. The asymmetries observed in penumbral grains, in the inner penumbra close to the umbra, can be reproduced by considering a vertical magnetic upflow of material hotter than the background.

Exoplanetary radio emissions: a future observation method

Jean-Mathias Grießmeier

Institute of Theoretical Physics, Technical University of Braunschweig

Similarly to the magnetized planets of the solar system, giant exoplanets are expected to be strong nonthermal radio emitters. This is especially true for close-in giant exoplanets ("Hot Jupiters"), where the interaction of the planet with the stellar wind is believed to be much stronger than for planets at larger orbital distances. Also, radio detection would yield additional information about the emitting planet, turning the search for radio emission from extrasolar planets into a useful additional observation method. Different parameters defining the expected exoplanetary radio flux are reviewed and discussed. It is shown that for certain planets the anticipated radio flux is strong enough to allow ground-based detection in the near future.

Energetic particles in the Jovian magnetosphere and their relation to auroral emissions

Ana Teresa Monteiro Tomás

Max Planck Institute for Solar System Research

Based on 33 of the Galileo orbits energetic particle and magnetic field properties in the transition region between the dipolar and the current sheet region of the Jovian magnetosphere are determined. The prime focus of the work is on the analysis and interpretation of the electron pitch angle distribution (PAD).

The relation between the electron PAD boundary and the secondary auroral oval, a discrete feature observed equatorward of the main auroral oval is then discussed. Magnetic field models are used to trace field lines threading the boundary in the equatorial plane, to the Jovian ionosphere. The study of the electron PAD boundary in the equatorial plane is further developed by simulating electron pitch angle distribution changes under the assumption of adiabatic motion in order to explain the observed distributions. Furthermore the possibility of whistler wave generation as an important electron scattering mechanism leading to pitch angle diffusion is discussed.

The resulting precipitation fluxes are estimated and compared to the auroral observations. It is concluded that the PAD boundary is the magnetospheric source region of the secondary auroral oval.

Thermal evolution of the martian interior

Monika Buske

Max Planck Institute for Solar System Research

On Mars young volcanism, tectonic activity and strong geoid anomalies are concentrated in only one region, the Tharsis bulge. These observations lead to the hypothesis that the thermal convection pattern in the martian mantle differs from that in Earth and is dominated by a few or maybe only a single strong plume under the Tharsis region.

A convection pattern with a strong reduced number of plumes can be observed in numerical models for Mars that include the endothermic phase transition from gamma-spinel to perovskite which may appear in Mars close to the core-mantle boundary.

In refined three-dimensional spherical convection models we investigate the thermal evolution of the martian mantle including its secular cooling. In these models the viscosity is depth dependent and is controlled by the horizontally averaged temperature through an Arrhenius law. The radial viscosity profile changes with time and in particular the growth of lithospheric thickness with time can be modelled in this way. In addition the depth dependence of the thermal expansivity and the depth and temperature dependence of the thermal conductivity are taken into account and their effects on the convection pattern and the thermal evolution are investigated. The temperature at the core-mantle boundary is time dependent and its variation is controlled by the heat flux from the core to the mantle. The model history of core temperature and heat flow allows to draw inferences on the existence and ultimate demise of a martian dynamo.

Magnetic flux emergence in the photosphere of the Sun

Mark Cheung

Max Planck Institute for Solar System Research

Magnetic flux emergence is associated with much of the dynamic phenomena observed in the solar atmosphere. The emergence is the passage of flux through the photosphere. This is the region where radiation becomes the dominant form of energy transport. In order to understand the emergence process, it is necessary to consider the effects of both magneto-convection and radiation. We have carried out 3D radiative magnetohydrodynamics (MHD) simulations to address this question. Having included the relevant physics, we directly compare the simulation results with observations.

List of Posters

Sun and Heliosphere

• S1 - Julián Blanco Rodríguez (IA Gö): High resolution observations of polar faculae
• S2 - Bruno Sánchez-Andrade Nuño (IA Gö): Analysis of a wide chromospheric active region
• S3 - Markus Sailer (IA Gö): Anisoplanatic optical transfer functions for Adaptive Optics supported image reconstruction
• S4 - Vasily Zakharov (MPS): A comparative study of the contrast of solar magnetic elements in CN and CH
• S5 - Clementina Sasso (MPS): Paschen-Back effect influence on the He I 1083.0 nm multiplet
• S6 - Lotfi Yelles Chaouche (MPS): Diagnostics of a simulated flux tube emergence
• S7 - Lucasz Matloch (MPS): Modelling of solar mesogranulation
• S8 - Jean Santos (MPS): Derivation of plasma flow velocities using photospheric magnetic field measurements
• S9 - Maxim Kramar (MPS): On the possibility of reconstruction of the coronal magnetic field from the spectropolarimetric observations of magnetically sensitive infrared lines
• S10 - Redouane Mecheri (MPS): Beam instabilities in a coronal funnel within the multi-fluid description
• S11 - Guadalupe Muñoz (MPS): Determination of coronal mass ejections arrival to Earth applied to space weather forecast
• S12 - Michael Heuer (MPS): A study on diffusion plateaus of protons in the fast solar wind
• S13 - Laura Balmaceda (MPS): Solar irradiance since Maunder minimum

Planets and Small Bodies

• P1 - Martin Schrinner (MPS): Mean-field view on geodynamo models
• P2 - Denise Tortorella (IG Gö and MPS): Effects of density stratification on thermal convection in rotating spherical shells
• P3 - Martin Tschimmel (MPS): Atmospheric water vapour on Mars - results from the PFS instrument on Mars Express
• P4 - Luca Maltagliati (MPS): Water vapour retrieval in Mars' atmosphere with OMEGA experiment onboard Mars Express
• P5 - Rupali Arunkumar Mahajan (MPS): Modelling Martian polar caps
• P6 - Ganna Portyankina (MPS): Lee wave clouds in the HRSC images: wind velocity measurements
• P7 - Richard Moissl (MPS): Planned observations with the Venus Monitoring Camera
• P8 - Stefan Schröder (MPS): Investigating the surface of Titan using Huygens' Descent Imager / Spectral Radiometer
• P9 - Ryu Saito (MPS): Generation of planetary waves near the surface in a general circulation model of the Martian atmosphere
• P10 - Esa Vilenius (MPS): SIR on SMART-1 - Working towards an instrument function
• P11 - Yevgen Grynko (MPS): LASCO C3 observations of comets 96P/Machholz 1 and C/2004 F4 Bradfield
• P12 - Cecilia Tubiana (MPS): In situ dust analysis with ROSETTA comet Churyumov-Gerasimenko
• P13 - Ingo von Borstel (IGEP BS): Dust trapping and manipulation for dust cloud experiments under microgravity conditions

Earth and Planetary Magnetospheres

• M1 - Dragos Ovidiu Constantinescu (IGEP BS): Wave sources location using CLUSTER data
• M2 - Yasuhito Narita (IGEP BS): Bow shock upstream and downstream waves
• M3 - Sebastian Schäfer (IGEP BS): Field line resonances as seen by CLUSTER
• M4 - Evgeny Panov (MPS): Cluster observation of perpendicular electromagnetic waves at the magnetopause
• M5 - Alexander Bößwetter (ITP BS): Global 3d hybrid simulation study of the Martian plasma boundaries
• M7 - Elena Kronberg (MPS): Mass release at Jupiter - substorm-like processes in the jovian magnetotail
• M8 - Aikaterini Radioti (MPS): Ion composition in the magnetosphere of Jupiter
• M9 - Gero Kleindienst (IGEP BS): ULF-waves in the Kronian magnetosphere
• M10 - Elias Roussos (MPS): Plasma interactions at Mars and the inner moons of Saturn: Results from data analysis and simulations

Miscellaneous

• O1 - Sabine Preusse (MPS): Interaction between Hot Jupiters and their stars
• O2 - Emre Ishik (MPS): Magnetic field generation and transport in cool stars
• O3 - Alina Semenova (MPS): Doppler imaging of Sigma Geminorum
• O4 - Lucas Paganini (MPS): Chirp Transform Spectrometers: characterization and improvement of the power density accuracy