Walter Morinobu Nakaema1, Eduardo Landulfo1, Anderson Zanardi Freitas1, Ricardo E. Samad1, Nilson Dias Vieira Jr1, Gesse Eduardo Calvo Nogueira1, Sônia Licia Baldochi1, Kamil Stelmaszczyk2

1Instituto de Pesquisas Energéticas e Nucleares -  Universidade de São Paulo
2Freie Universität Berlin

 

This work has as objective to implement a method to the determination of charge densities of aerosol particles and cloud droplets, electrically charged. For this purpouse, it is intended to use a non linear high power LIDAR (Light Detection and Ranging) system with the Second Harmonic Generation (SHG) generated in the interface between droplets and/or aerosols electrically charged with the environment. The detection of the Second Harmonic (SH) signal will be able to give information about the charge surface density of these droplets and aerosols and to quantify their influence on cloud condensation nuclei (CCN) and ice nuclei (IN). Because of the laser high power (1012 W), it is common to verify also the generation of a stationary plasma state in the air. The first part of the project will be carried at Freie Universität Berlin, in Berlin (Germany), where the installation of a system to generate and measure the SH is already in an advanced state of implementation and is whithin the context of the project Charge Detection In Clouds And Atmospheric Aerosols By Means of SHG At The Droplet-Air Interface, carried out by Dr Kamil Stelmaszczyk since 2005. Once established the parameters in laboratory, it will be done the first measurements of charged atmospheric particles, using non linear LIDAR to generate the Second Harmonic (SH). The second stage of this project aims to adapt the system and instruments developed in Berlin to the Center for Lasers and Applications (CLA) at the Instituto de Pesquisas Energéticas e Nucleares (IPEN) located at University of São Paulo, Brazil, where is in improvement, a T-cube (Table Top Terawatt) unit with Ti-Sapphire laser 830 nm wavelength. It is expected that this system generates pulses with 100 mJ of energy and the time duration less than 100fs (generating a peak of 1012 watt or one terawatt). Finally, it is intended to become an operational method in Brazil for monitoring the aerosol layer and cloud formation with accuracy, through the additional information of the SHG that will add to the information obtained by the elastic LIDAR system already operational at the CLA.