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SUMMARY:Fast Models of Multiple Lyman-Alpha Scattering for Exospheric Inve
 rsion
DTSTART;VALUE=DATE-TIME:20261120T151500Z
DTEND;VALUE=DATE-TIME:20261120T153000Z
DTSTAMP;VALUE=DATE-TIME:20261010T165725Z
UID:indico-contribution-1498@indico.uni.edu.pe
DESCRIPTION:Speakers: Isaac Leonardo Huaira Lopez (Universidad Nacional Ma
 yor de San Marcos)\nLyman-alpha observations are widely used to study hydr
 ogen exospheres. At high altitudes\, measured intensity can often be appro
 ximated as proportional to hydrogen density integrated along the line of s
 ight. At lower altitudes\, the exosphere becomes optically thick\, and abs
 orption and multiple scattering produce a nonlocal relation between densit
 y and observed intensity. Full radiative-transfer calculations capture the
 se effects\, but their computational cost limits their use in inverse mode
 ls requiring many forward evaluations.\n\nWe compare two approaches to red
 uce this cost. The first uses a surrogate model trained on high-fidelity r
 adiative-transfer calculations. Rather than replacing the physical model\,
  the surrogate predicts corrections to optically thin or single-scattering
  intensity caused by attenuation and multiple scattering. The second reduc
 es the multiple-scattering operator itself using low-rank\, reduced-basis\
 , and simplified representations that preserve the main spatial coupling w
 ith fewer calculations. Both methods will be tested on the same asymmetric
  hydrogen distributions and viewing geometries. We will compare radiance e
 rrors\, execution times\, memory requirements\, performance across optical
  depths\, and sensitivity to density and temperature parameters. Our goal 
 is to identify a fast\, accurate radiative-transfer approximation suitable
  for retrievals of exospheric structure from Lyman-alpha images\, includin
 g observations from the Carruthers Geocorona Observatory.\n\nhttps://indic
 o.uni.edu.pe/event/192/contributions/1498/
LOCATION:Universidad Nacional de San Agustin de Arequipa Facultad de Cienc
 ias
URL:https://indico.uni.edu.pe/event/192/contributions/1498/
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