49 research outputs found
The Main Pillar: Assessment of Space Weather Observational Asset Performance Supporting Nowcasting, Forecasting and Research to Operations
Space weather forecasting critically depends upon availability of timely and reliable observational data. It is therefore particularly important to understand how existing and newly planned observational assets perform during periods of severe space weather. Extreme space weather creates challenging conditions under which instrumentation and spacecraft may be impeded or in which parameters reach values that are outside the nominal observational range. This paper analyzes existing and upcoming observational capabilities for forecasting, and discusses how the findings may impact space weather research and its transition to operations. A single limitation to the assessment is lack of information provided to us on radiation monitor performance, which caused us not to fully assess (i.e., not assess short term) radiation storm forecasting. The assessment finds that at least two widely spaced coronagraphs including L4 would provide reliability for Earth-bound CMEs. Furthermore, all magnetic field measurements assessed fully meet requirements. However, with current or even with near term new assets in place, in the worst-case scenario there could be a near-complete lack of key near-real-time solar wind plasma data of severe disturbances heading toward and impacting Earth's magnetosphere. Models that attempt to simulate the effects of these disturbances in near real time or with archival data require solar wind plasma observations as input. Moreover, the study finds that near-future observational assets will be less capable of advancing the understanding of extreme geomagnetic disturbances at Earth, which might make the resulting space weather models unsuitable for transition to operations
The Electron Proton Helium INstrument as an Example for a Space Weather Radiation Instrument
The near-Earth energetic particle environment has been monitored since the
1970's. With the increasing importance of quantifying the radiation risk for,
e.g. for the human exploration of the Moon and Mars, it is essential to
continue and further improve these measurements. The Electron Proton Helium
INstrument (EPHIN) on-board SOHO continually provides these data sets to the
solar science and space weather communities since 1995. Here, we introduce the
numerous data products developed over the years and present space weather
related applications. Important design features that have led to EPHINs success
as well as lessons learned and possible improvements to the instrument are also
discussed with respect to the next generation of particle detectors
Upstream magnetospheric ion flux tube within a magnetic cloud: Wind/STICS
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95514/1/grl16367.pd
Association of Low‐Charge‐State Heavy Ions up to 200 R e upstream of the Earth's bow shock with geomagnetic disturbances
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94741/1/grl14934.pd
Measurements of Forbush decreases at Mars: both by MSL on ground and by MAVEN in orbit
The Radiation Assessment Detector (RAD), on board Mars Science Laboratory's
(MSL) Curiosity rover, has been measuring ground level particle fluxes along
with the radiation dose rate at the surface of Mars since August 2012. Similar
to neutron monitors at Earth, RAD sees many Forbush decreases (FDs) in the
galactic cosmic ray (GCR) induced surface fluxes and dose rates. These FDs are
associated with coronal mass ejections (CMEs) and/or stream/corotating
interaction regions (SIRs/CIRs). Orbiting above the Martian atmosphere, the
Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft has also been
monitoring space weather conditions at Mars since September 2014. The
penetrating particle flux channels in the Solar Energetic Particle (SEP)
instrument onboard MAVEN can also be employed to detect FDs. For the first
time, we study the statistics and properties of a list of FDs observed in-situ
at Mars, seen both on the surface by MSL/RAD and in orbit detected by the
MAVEN/SEP instrument. Such a list of FDs can be used for studying
interplanetary CME (ICME) propagation and SIR evolution through the inner
heliosphere. The magnitudes of different FDs can be well-fitted by a power-law
distribution. The systematic difference between the magnitudes of the FDs
within and outside the Martian atmosphere may be mostly attributed to the
energy-dependent modulation of the GCR particles by both the pass-by ICMEs/SIRs
and the Martian atmosphere
Modeling the variations of Dose Rate measured by RAD during the first MSL Martian year: 2012-2014
The Radiation Assessment Detector (RAD), on board Mars Science Laboratory's
(MSL) rover Curiosity, measures the {energy spectra} of both energetic charged
and neutral particles along with the radiation dose rate at the surface of
Mars. With these first-ever measurements on the Martian surface, RAD observed
several effects influencing the galactic cosmic ray (GCR) induced surface
radiation dose concurrently: [a] short-term diurnal variations of the Martian
atmospheric pressure caused by daily thermal tides, [b] long-term seasonal
pressure changes in the Martian atmosphere, and [c] the modulation of the
primary GCR flux by the heliospheric magnetic field, which correlates with
long-term solar activity and the rotation of the Sun. The RAD surface dose
measurements, along with the surface pressure data and the solar modulation
factor, are analysed and fitted to empirical models which quantitatively
demonstrate} how the long-term influences ([b] and [c]) are related to the
measured dose rates. {Correspondingly we can estimate dose rate and dose
equivalents under different solar modulations and different atmospheric
conditions, thus allowing empirical predictions of the Martian surface
radiation environment
Comparisons Between Model Predictions and Spectral Measurements of Charged and Neutral Particles on the Martian Surface
Detailed measurements of the energetic particle radiation environment on the surface of Mars have been made by the Radiation Assessment Detector (RAD) on the Curiosity rover since August 2012. RAD is a particle detector that measures the energy spectrum of charged particles (10 to approx. 200 MeV/u) and high energy neutrons (approx 8 to 200 MeV). The data obtained on the surface of Mars for 300 sols are compared to the simulation results using the Badhwar-O'Neill galactic cosmic ray (GCR) environment model and the high-charge and energy transport (HZETRN) code. For the nuclear interactions of primary GCR through Mars atmosphere and Curiosity rover, the quantum multiple scattering theory of nuclear fragmentation (QMSFRG) is used. For describing the daily column depth of atmosphere, daily atmospheric pressure measurements at Gale Crater by the MSL Rover Environmental Monitoring Station (REMS) are implemented into transport calculations. Particle flux at RAD after traversing varying depths of atmosphere depends on the slant angles, and the model accounts for shielding of the RAD "E" dosimetry detector by the rest of the instrument. Detailed comparisons between model predictions and spectral data of various particle types provide the validation of radiation transport models, and suggest that future radiation environments on Mars can be predicted accurately. These contributions lend support to the understanding of radiation health risks to astronauts for the planning of various mission scenario
Mars’ Surface Radiation Environment Measured with the Mars Science Laboratory’s Curiosity Rover
The Radiation Assessment Detector (RAD) on the Mars Science Laboratory’s Curiosity rover began making detailed measurements of the cosmic ray and energetic particle radiation environment on the surface of Mars on 7 August 2012. We report and discuss measurements of the absorbed dose and dose equivalent from galactic cosmic rays and solar energetic particles on the Martian surface for ~300 days of observations during the current solar maximum. These measurements provide insight into the radiation hazards associated with a human mission to the surface of Mars, and provide an anchor point to model the subsurface radiation environment, with implications for microbial survival times of any possible extant or past life, as well as for the preservation of potential organic biosignatures of the ancient Martian environment