Energetic particle monitoring in space: three-decades of experience at IEPSAS

The application of laser diffraction particle monitoring to the performance optimisation of a pilot clarifier and full-scale rapid gravity filters (RGF), operating on water supply works in Hampshire, is described. Furthermore the dosing of powdered activated carbon (PAC) into the works' clarifiers has been evaluated in terms of RGF performance. A costly proposal to install a third filter medium was subsequently abandoned when it was found that particle numbers in the filtered water were consistently below 1×102/ml. Various combinations and doses of coagulants and flocculant aids, shown to give optimum particulates removal during intensive jar testing trials, were transferred to the pilot clarifier. Particle monitoring enabled a more accurate derivation of suitable blanket chemistry and optimum blanket heights than turbidity changes. Raw water turbidities were 10-15 NTU at start-up with corresponding counts beyond the upper limit of the particle monitor. An on-line dilution system was developed to overcome this problem. Latex bead (4.33 μm) and Lycopodium spore (4-5 μm) suspensions (about 1 × 109 particles) were injected into the pilot clarifier to assess the removal efficiency of Cryptosporidium-sized particles. Reductions of about 1.7 log and 2.6 log were achieved for the beads and spores, respectively. Particle distributions of various PAC's and a bentonite were obtained in order to assess their potential effects on the coagulation process during clarification. Bentonite was also beneficial as an on-line means of checking particle monitor response and calibration. The works' filters achieved 1.5 to 2.0 log removals of 2-5 μm particles without media addition or operational changes. Combined clarification and filtration gave better particulates removal than two-stage microfiltration.

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Empirical Model of 10 – 130 MeV Solar Energetic Particle Spectra at 1 AU Based on Coronal Mass Ejection Speed and Direction

Solar Physics ◽

10.1007/s11207-021-01779-4 ◽

2021 ◽

Vol 296 (2) ◽

Author(s):

Alessandro Bruno ◽

Ian G. Richardson

Keyword(s):

Coronal Mass Ejection ◽

Empirical Model ◽

Energetic Particle ◽

Solar Energetic Particle ◽

Particle Spectra ◽

Ejection Speed ◽

Mass Ejection

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Unusual enhancement of ~ 30 MeV proton flux in an ICME sheath region

Earth Planets and Space ◽

10.1186/s40623-021-01362-y ◽

2021 ◽

Vol 73 (1) ◽

Author(s):

Mitsuo Oka ◽

Takahiro Obara ◽

Nariaki V. Nitta ◽

Seiji Yashiro ◽

Daikou Shiota ◽

...

Keyword(s):

Shock Front ◽

Energetic Particle ◽

Leading Edge ◽

Solar Energetic Particle ◽

Interplanetary Shock ◽

Proton Event ◽

Sheath Region ◽

Time Profiles ◽

Energetic Particle Flux ◽

Mev Protons

AbstractIn gradual Solar Energetic Particle (SEP) events, shock waves driven by coronal mass ejections (CMEs) play a major role in accelerating particles, and the energetic particle flux enhances substantially when the shock front passes by the observer. Such enhancements are historically referred to as Energetic Storm Particle (ESP) events, but it remains unclear why ESP time profiles vary significantly from event to event. In some cases, energetic protons are not even clearly associated with shocks. Here, we report an unusual, short-duration proton event detected on 5 June 2011 in the compressed sheath region bounded by an interplanetary shock and the leading edge of the interplanetary CME (or ICME) that was driving the shock. While < 10 MeV protons were detected already at the shock front, the higher-energy (> 30 MeV) protons were detected about four hours after the shock arrival, apparently correlated with a turbulent magnetic cavity embedded in the ICME sheath region.

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