1. MPSE 2014, Warsaw 3-5 June INVESTIGATION OF MARTIAN LIGHTNING ACTIVITY AND THE SUBSURFACE OF MARS Joanna Kozakiewicz 1, Andrzej Kulak 1,2, Janusz Mlynarczyk 2, Krzysztof Zietara 1, Jerzy Kubisz 1 1 Jagiellonian University, Krakow, Poland 2 AGH University of Science and Technology, Krakow, Poland MPSE 2014, Warsaw 3-5 June

2. ELF Electromagnetic Waves ELF (Extremely Low Frequency) EM waves: 3Hz-3kHz Generated by lightning activity Propagate on very long distance – low attenuation Propagate in the waveguide made of two spherical conductive layers: –ionosphere –ground Investigation of Martian environment by ELF: –global scale –lightning activity –structure of the ionosphere –structure of the subsurface groundwater reservoirs Propagation parameters

3. MPSE 2014, Warsaw 3-5 June Schumann Resonance ELF waves generate the Schumann resonance phenomenon Schumann resonance frequencies can be given by: where: f 0n – resonance frqquencies for an ideal cavity, c – the speed of light, v – the ELF waves phase velocity, R – the planetary radius, and n – the resonance mode.

4. MPSE 2014, Warsaw 3-5 June ELF Station Receiver ELA10 sampling rate 900 1/s 12 V / 800 mW time error < 200  s Magnetic AA1130 bandwith 0.01  300 Hz lenght 1000 mm mass 15 kg power 12 V / 25 mW Electric AE7 bandwith 0.01  300 Hz lenght 2000 mm mass 10 kg power 10 V / 50 mW Automatic measuring station has been operating since 2005 in Bieszczady, Poland

5. MPSE 2014, Warsaw 3-5 June Method Solution of Maxwell’s equations in non-uniform mediums An analytical approach: –fast analysis –> numerical methods – weeks, analytical – minutes –testing numerical modeling –possibility for studying inverse problems –relationship between propagation parameters and environmental properties Propagation Parameters ELF Measurements Environmental properties Analytical Method

6. MPSE 2014, Warsaw 3-5 June d1d1 σ 1, ε 1 σ 2, ε 2 d1d1 σ 1, ε 1 σ 2, ε 2 DRY model: no liquid water σ 1 = 10 -7 S/m, d 1 = 40 km, σ 2 = 10 -2 S/m BRINE model: high salinity water σ 1 = 10 -7 S/m, d 1 = 10 km, σ 2 = 10 -2 S/m AQUA model: low salinity water σ 1 = 10 -7 S/m, d 1 = 10 km, σ 2 = 10 -4 S/m Environment of Mars Scenarios with the hypothetical models of the planetary subsurface and ELF sources A source of an ELF – the delta function and an amplitude of 1C·km. Double-layered models of the ground: Clifford et al., 2010 d1d1 σ 1, ε 1 σ 2, ε 2

7. MPSE 2014, Warsaw 3-5 June Results The waveforms of the ELF pulses at a propagation distance of 5 Mm The SR first mode frequency in a function of the depth and conductivity of the first layer. The conductivity of the second layer is 10 -4 S/m. Schumann resonance spectra for three ground models –black – ideal ground, blue – BRINE, yellow – AQUA, red – DRY Finite conductivity of the ground have a significant impact on the delay and the amplitude of the observed waveforms. The presence of aquifers increase significantly the Schumann resonance frequencies and amplitudes.

8. MPSE 2014, Warsaw 3-5 June Station on Mars 1.Fully autonomous station with magnetic and electric antennas 2.Autonomous version with only electric field antenna – mass reduction 3.Separate magnetometer as a part of MARS vehicle (electric antenna) Room and resources for other scientific equipment Power: 12 W Power Management Unit Communication Unit Solar Panel Li-Ion Battery Computer Unit Magnetometer Device 1 Device 2 UHF Communication antenna. Electric antenna Magnetic antennas

9. MPSE 2014, Warsaw 3-5 June External electronic warm box (EEWB): 850mm x 850mm x 150mm Antennas: two orthogonal magnetic and one electric: 700mm x 10mm Internal electronic warm box (IEWB): 645mm x 645mm x 100mm Weight: 15 kg 3D Visualisation

10. MPSE 2014, Warsaw 3-5 June Conclusions The developed instruments and methodology can be used to measured properties of the subsurface, atmosphere and intensity of electrical discharges on Mars. Finite conductivity of the ground strongly influences the Schumann resonance parameters. On Mars, its contribution is greater than the one related with the different ionospheric profiles. Since the presented model is fully analytical, it is computationally efficient and can be very useful to find inverse solutions. It takes minutes to acquire results for different environmental models, which with the numerical modeling would take weeks. Data acquired by the ELF receiver will explicitly prove the existence of lightning activity on Mars. Our method can be applied also to other objects in the Solar System which have electromagnetic cavities.

11. MPSE 2014, Warsaw 3-5 June Thank You for Your Attention