1. LOFAR Lightning Imaging (LOFLI)
Contact: Olaf Scholten, KVI-CART
During thunderstorm many pulses observed with LBA-LOFAR, coincident in many (distant) stations. These are due to ‘stepping of lightning discharge’.
Aim: Find their sources in the sky to learn about physics of lightning development
Construct (using time of arrival procedure) a 3D map of their sources
Typical time-trace as measure by LOFAR
Typical time-trace as measure by LOFAR
Construct (using time of arrival procedure) a 3D map of their sources
1-1 Can the polarization of the measured pulses be used to obtain leader-step direction?
1-2 Can the pulse-forms be used to obtain information on charge distribution is leader step?

2. LOFAR Cosmic Ray Detection(LOCRD)
Coherent radio emission from Cosmic-ray induced air showers determines property of initial CR.
Aim: use the radio emission (Intensity & polarization & frequency) to learn about the properties of the initial cosmic ray and thus its source.
Determine composition CR; (extra)galactic?
CR & LOFAR
Cosmic-ray radio-intensity footprint
Typical time-trace as measure by LOFAR
Construct (using time of arrival procedure) a 3D map of their sources
2-1 Is the radio footprint sensitive to the physics of the first collisions?
2-2 Is it possible to use radio emission for measuring high energy gammas?:
Nature, 531 p70 (3 maart 2016)

3. Muon “problem” in air showers: Calculated muon number well below the data
Fluorescence data give perfect fit:
Determines Xmax and Energy
Possible reasons
New Physics
Rho-meson
Antinucleon
Surface detectors counts higher than expected
(QGSJet-II-04, LHC compatible)
3-1 What are possible explanations for the muon excess in air showers?
PRL 117, (2016)

4. High Energy Neutrino Physics (HENP)
High energy neutrinos (energies >1014eV) are seen with the IceCube detector.
Aim: What is the source? – Dark Matter? – Active Galactic Nuclei? – Gamma Ray Burst?
What is the physics around AGN; understand HEN production.
Schematic indication of possible mechanism for neu-production is Black-hole-collapse
Southpole
High energy neutrinos in IceCube
4-1 Mechanism for creating high-energy neutrinos and hadrons.
4-2 Understand mechanism for High-energy gamma production, relation with cosmic rays?

5. Possible projects Contact: Olaf Scholten, KVI-CART Scholten@kvi.nl
Lightning:
1-1 Can the polarization of the measured pulses be used to obtain leader-step direction?
1-2 Can the pulse-forms be used to obtain information on charge distribution is leader step?
Cosmic rays:
2-1 Is the radio footprint sensitive to the physics of the first collisions?
2-2 Is it possible to use radio emission for measuring high energy gammas?:
Muons in air showers:
3-1 What are possible explanations for the muon excess in air showers?
Sources of high energy neutrinos:
4-1 Mechanism for creating high-energy neutrinos and hadrons.
4-2 Understand mechanism for High-energy gamma production, relation with cosmic rays?
4-3 = 2-2