Monthly Proton Flux Monthly Proton Flux Matteo Palermo (University - PowerPoint PPT Presentation

Properties of The Forbush Properties of The Forbush decreases measured by AMS decreases measured by AMS on the ISS on the ISS Monthly Proton Flux Monthly Proton Flux Matteo Palermo (University of Hawaii) on behalf of the AMS Collaboration Physics and Astronomy Department University of Hawaii at Manoa Honolulu, Hawaii, US 17/07/2017 Matteo Palermo 1

AMS Collaboration AMS Collaboration AMS was installed on the International Space Station on May 19, 2011 In 6 years of operation, AMS has measured over 100 billion events. It will continuously take data for the entire duration of the ISS UHM 17/07/2017 Matteo Palermo 2

Particle Identification with AMS Particle Identification with AMS AMS is a general purpose detector which measures particles in the GV-TV rigidity range 17/07/2017 Matteo Palermo 3

Cosmic Rays (CR) Cosmic Rays (CR) Nuclei with AMS Nuclei with AMS AMS measures all CR species with error at % level up to Fe and above It will improve our knowledge of CR sources, acceleration mechanisms and propagation More details in ICRC 2017 CR-D session: A. Oliva, Q. Yan, V. Choutko 17/07/2017 Matteo Palermo 4

Proton and He Monthly Fluxes Proton and He Monthly Fluxes ICRC 2017 CR-D session : presentation from C. Consolandi Highlight talk by V. Bindi At low rigidities, not only long-term solar modulation but also short-term solar activity 17/07/2017 Matteo Palermo 5

AMS Daily Proton Flux AMS Daily Proton Flux June 21, 2015 Preliminary Data Please refer to the AMS forthcoming publication in PRL 17/07/2017 Matteo Palermo 6

AMS Daily Proton Flux AMS Daily Proton Flux AMS observed fast decreases in the daily proton flux Preliminary Data Please refer to the AMS forthcoming publication in PRL June 23, 2015 17/07/2017 Matteo Palermo 7

AMS Daily Proton Flux AMS Daily Proton Flux Decreases may last several days Preliminary Data Please refer to the AMS forthcoming publication in PRL June 27, 2015 17/07/2017 Matteo Palermo 8

AMS Daily Proton Flux AMS Daily Proton Flux This decrease lasted for 17 days June 30, 2015 Preliminary Data Please refer to the AMS forthcoming publication in PRL 17/07/2017 Matteo Palermo 9

AMS Daily Proton Flux AMS Daily Proton Flux Gradually AMS proton flux recovers to previous conditions July 7, 2015 Preliminary Data Please refer to the AMS forthcoming publication in PRL 17/07/2017 Matteo Palermo 10

Forbush Decreases (FD) Forbush Decreases (FD) ➢ Temporary decreases in the CR flux, followed by gradual recovery ➢ Often associated to passing of Interplanetary Coronal Mass Ejections (CME) and/or Corotating Interacting Regions (CIR) ➢ Some of them may be associated with the arrival of Solar Energetic Particles (SEP) accelerated at the Sun during CME or solar flares. 1.02-1.10 GV March 2012 Solar Energetic Particle and Forbush decrease event 3.14-3.41 GV 5.09-5.52 GV Preliminary Data 10.51-11.39 GV Please refer to the AMS forthcoming publication in PRL 20.00-21.68 GV Highlight talk by V. Bindi 17/07/2017 Matteo Palermo 11

FDs and SEPs FDs and SEPs Highlight talk by V. Bindi 17/07/2017 Matteo Palermo 12

Why studying FDs with AMS? Why studying FDs with AMS? ➢ Although FDs can be seen also on the ground (e.g by Neutron Monitors), the rigidity spectra of FDs and their time evolution are not precisely known ➢ The relationship with disturbances measured in the solar wind and FD behavior in rigidity is unknown ➢ Remove the short-term effects to better study the long-term solar modulation March 2012 Solar Energetic Particle and Forbush decrease event 2.40-2.67 GV 3.29-3.64 GV 5.37-5.90 GV 10.1-11.0 GV Preliminary Data 19.5-21.1 GV Please refer to the AMS forthcoming publication in PRL 17/07/2017 Matteo Palermo 13

Forbush Decreases Forbush Decreases Identification Identification Characterize the day-to-day variability on AMS proton flux for each rigidity bin 1. Select quiet periods (~ 1 month) 2. Normalize the daily flux to the average of the first 3 days 3. Calculate standard deviation (SD ) of the daily flux distribution Proton 2.40-2.67 GV Preliminary Data 3.29-3.64 GV Please refer to the AMS 5.37-5.90 GV forthcoming publication in PRL 10.1-11.0 GV 19.5-21.1 GV 17/07/2017 Matteo Palermo 14

Day-to-day Variability Day-to-day Variability Average Variability Solar wind effects Preliminary Data Please refer to the AMS forthcoming publication in PRL 17/07/2017 Matteo Palermo 15

Forbush Decreases Forbush Decreases Identification Identification Look for significant decreases in the daily proton flux, for each rigidity bin Preliminary Data, please refer to the AMS forthcoming publication in PRL 2.97-3.29 GV Normalized Flux at 2.97–3.29 GV Preliminary Data, please refer to the AMS forthcoming publication in PRL 16.6-18.0 GV Normalized Flux at 16.6–18.0 GV 17/07/2017 Matteo Palermo 16

FD Characteristics FD Characteristics Start date: date when decrease is first observed Date of minimum: date when majority of rigidity reach a minimum value Recovery date: date when normalized flux is within 2 SD of day-to-day variability Duration: number of days a decrease is observed Maximum rigidity: highest rigidity that shows a decrease Maximum decrease at 2 GV: percent decrease of the flux in the rigidity bin around 2 GV on the date of minimum. 2.40-2.67 GV 3.29-3.64 GV Preliminary Data 5.37-5.90 GV Please refer to the AMS 10.1-11.0 GV forthcoming publication in PRL 19.5-21.1 GV 17/07/2017 Matteo Palermo 17

FD Characteristics FD Characteristics Start date: date when decrease is first observed Date of minimum: date when majority of rigidity reach a minimum value Recovery date: date when normalized flux is within 2 SD of day-to-day variability Duration: number of days a decrease is observed Maximum rigidity: highest rigidity that shows a decrease Maximum decrease at 2 GV: percent decrease of the flux in the rigidity bin around 2 GV on the date of minimum. 2.40-2.67 GV 3.29-3.64 GV 5.37-5.90 GV Preliminary Data Please refer to the AMS 10.1-11.0 GV forthcoming publication in PRL 19.5-21.1 GV 17/07/2017 Matteo Palermo 18

FD Characteristics FD Characteristics Start date: date when decrease is first observed Date of minimum: date when majority of rigidity reach a minimum value Recovery date: date when normalized flux is within 2 SD of day-to-day variability Duration: number of days a decrease is observed Maximum rigidity: highest rigidity that shows a decrease Maximum decrease at 2 GV: percent decrease of the flux in the rigidity bin around 2 GV on the date of minimum. 2.40-2.67 GV 3.29-3.64 GV 5.37-5.90 GV Preliminary Data Please refer to the AMS 10.1-11.0 GV forthcoming publication in PRL 19.5-21.1 GV 17/07/2017 Matteo Palermo 19

FD Characteristics FD Characteristics Start date: date when decrease is first observed Date of minimum: date when majority of rigidity reach a minimum value Recovery date: date when normalized flux is within 2 SD of day-to-day variability Duration: number of days a decrease is observed Maximum rigidity: highest rigidity that shows a decrease Maximum decrease at 2 GV: percent decrease of the flux in the rigidity bin around 2 GV on the date of minimum. 2.40-2.67 GV 3.29-3.64 GV 5.37-5.90 GV Preliminary Data Please refer to the AMS 10.1-11.0 GV forthcoming publication in PRL 19.5-21.1 GV 17/07/2017 Matteo Palermo 20

FD Characteristics FD Characteristics Start date: date when decrease is first observed Date of minimum: date when majority of rigidity reach a minimum value Recovery date: date when normalized flux is within 2 SD of day-to-day variability Duration: number of days a decrease is observed Maximum rigidity: highest rigidity that shows a decrease Maximum decrease at 2 GV: percent decrease of the flux in the rigidity bin around 2 GV on the date of minimum. 2.40-2.67 GV 3.29-3.64 GV 5.37-5.90 GV Preliminary Data Please refer to the AMS 10.1-11.0 GV forthcoming publication in PRL 19.5-21.1 GV 17/07/2017 Matteo Palermo 21

FD Characteristics FD Characteristics Start date: date when decrease is first observed Date of minimum: date when majority of rigidity reach a minimum value Recovery date: date when normalized flux is within 2 SD of day-to-day variability Duration: number of days a decrease is observed Maximum rigidity: highest rigidity that shows a decrease Maximum decrease at 2 GV: percent decrease of the flux in the rigidity bin around 2 GV on the date of minimum. 2.40-2.67 GV 3.29-3.64 GV 5.37-5.90 GV Preliminary Data Please refer to the AMS 10.1-11.0 GV forthcoming publication in PRL 19.5-21.1 GV 17/07/2017 Matteo Palermo 22

FD Characteristics FD Characteristics Start date: date when decrease is first observed Date of minimum: date when majority of rigidity reach a minimum value Recovery date: date when normalized flux is within 2 SD of day-to-day variability Duration: number of days a decrease is observed Maximum rigidity: highest rigidity that shows a decrease Maximum decrease at 2 GV: percent decrease of the flux in the rigidity bin around 2 GV on the date of minimum. 2.40-2.67 GV 3.29-3.64 GV 5.37-5.90 GV Preliminary Data Please refer to the AMS 10.1-11.0 GV forthcoming publication in PRL 19.5-21.1 GV 17/07/2017 Matteo Palermo 23